Search

Machine learning is a promising method to model production processes and predict product quality. It is challenging to accurately model complex systems due to data scarcity, as mass customisation leads to various high-variety low-volume products. This study conceptualised knowledge accumulation, extraction, and transfer (KAET) to exploit the knowledge embedded in similar entities to address data scarcity. A sequential cross-product KAET (SeqTrans) is proposed to conduct KAET, integrating data preparation and preprocessing, feature selection (FS), feature learning (FL), and transfer learning (TL). The FS and FL modules conduct knowledge extraction and help address various practical challenges such as changing operating conditions and unbalanced datasets. In this paper, sequential TL is introduced to production modelling to conduct knowledge transfer among multiple entities. The first case study of auxetic material performance prediction demonstrates the effectiveness of sequential TL. Compared with conventional TL, sequential TL can achieve the same test mean square errors with 300 fewer training examples when facing data scarcity. In the second case study, balancing anomaly detection models were constructed for two gas turbines in the same series using real-world production data. With SeqTrans, the F1-score of the anomaly detection model of the data-poor engine was improved from 0.769 to 0.909. [ABSTRACT FROM AUTHOR]

This research is dedicated to advancing gas turbine technology for greener and more cost-effective commercial air transportation. The focus lies in optimizing the High Pressure Compressor (HPC) component of NASA’s Energy Efficient Engine (EEE) which compresses air prior to entering the combustion chamber. The goal for the research project was to improve the compressor’s pressure ratio from inlet to outlet to enhance the efficiency of the combustion process. Factors affecting compressor performance, such as blade twist angle, blade geometry, and shroud and hub tip clearance, are analyzed and optimized to improve efficiency and overall performance. Computational Fluid Dynamics (CFD) models were created within the Ansys software suite and successfully optimized by leveraging the San Diego Supercomputer Center. This research achieved a pressure ratio increase across the first four stages of a ten-stage compressor, surpassing NASA's 1980 model. This paper outlines the methodology, including geometry generation using Ansys BladeModeler, blade row meshing with TurboGrid, and CFX (Fluid dynamics) simulations. The optimization process involved multiple design iterations and a response surface method to attain the highest pressure ratio. The multidisciplinary approach underscores the potential of leveraging emerging technologies of CFD and High Performance Computing to significantly improve the efficiency of existing models, as exemplified by the successful optimization of the EEE’s HPC.

The transition from traditional aviation fuels to low-emission alternatives such as hydrogen is a crucial step towards a sustainable future for aviation. Conventional jet fuels substantially contribute to greenhouse gas emissions and climate change. Hydrogen fuel, especially "green" hydrogen, offers great potential for achieving full sustainability in aviation. Hybrid/electric/fuel cell technologies may be used for shorter flights, while long-range aircraft are more likely to combust hydrogen in gas turbines. Liquid hydrogen is necessary to minimize storage tank weight, but the required fuel systems are at a low technology readiness level and differ significantly from Jet A-1 systems in architecture, operation, and performance. This paper provides an in-depth review covering the development of liquid hydrogen fuel system design concepts for gas turbines since the 1950s, compares insights from key projects such as NASA studies and ENABLEH2, alongside an analysis of recent publications and patent applications, and identifies the technological advancements required for achieving zero-emission targets through hydrogen-fuelled propulsion. [Display omitted] • Review the evolution and advancements in liquid hydrogen gas turbine fuel systems. • Compare different liquid hydrogen fuel systems for aviation and aerospace applications. • Analyze 11 relevant reports/projects and 15 patents on liquid hydrogen fuel systems. • Identification of the key technical challenges to adopting liquid hydrogen as a fuel. • Potential solutions to address the challenges for next-generation aero engines. [ABSTRACT FROM AUTHOR]

Decarbonization of gas turbine combustion creates a pressing demand for new technical solutions for the combustion process. While switching to hydrogen fuels may solve the problem of carbon emissions and associated pollutants, it can also lead to stability issues for swirl-stabilized combustors due to its increased reactivity. However, with jet flame burner systems, the required flashback safety can be achieved with high axial flow velocities even for premixed combustion of 100% hydrogen fuel. The development of such an engineering solution, however, requires significant effort to reach the maturity of today's swirl burners. This study examines the capacity of a premixed multitube jet burner to manage the chemical reactivity change over a range of volumetric blends from pure natural gas (NG) to pure hydrogen fuel. NOx emissions are measured and analyzed for atmospheric tests. The changes in emissions originate not only from altered combustion chemistry but also from changes in flame shape and turbulence intensity. To get a deeper understanding of the NOx formation process, a low-order model is designed and compared to the experimental data of technically and perfectly premixed combustion tests. Parameter variations of the low-order model are conducted to assess the influences on the NOx emission production of the multijet burner. The information on the combustion process required for the model is obtained computationally and experimentally. Therefore, flame images are recorded and analyzed. [ABSTRACT FROM AUTHOR]

This paper presents the experimental results of a representative aircraft turbo-electric powertrain. The 180-kW hybrid gas-electric ground test rig was designed, fabricated, and experimentally evaluated. Hybrid turbo-electric power systems are an enabler for future medium- to long-range electrified aircraft, offering higher energy density over current battery technologies. Previous studies have focused on analytical models of turbo-electric power systems. However, as industry stakeholders continue to advance toward implementing turbo-electric parallel hybrid aircraft, there is a lack of practical knowledge regarding their implementation. The objectives of this study are twofold. First, the study aims to evaluate the real-time transient performance of turbo-electric aircraft. The second objective aims to characterize the real-world challenges of safely constructing and operating a hybrid turbo-electric aircraft. To accomplish both objectives, a turboprop-powered ground test vehicle was designed and fabricated. The ground test vehicle was constructed from a modified Cessna-172 aircraft, a modified 180-kW PBS-TP100 turboprop, two wing-mounted electric motors, and a purpose-built hybrid-turbo-electric powertrain. A portion of the turboprop shaft power is extracted to generate electricity for the battery system and wing-mounted electric motors. The test vehicle was successfully brought to full engine power and the wing-mounted electric motors were run through a series of operating points to experimentally evaluate transient electrical and mechanical performance. Observations are made regarding the interdependent time responses of the electromechanical systems. Results from the test run include engine performance metrics, current, voltage, and acoustic data. The generator peaked at 4-kW and was augmented by 13-kW of battery power to drive distributed propulsors, while the turboprop generated 142-kW of power for the variable pitch propeller. Practical recommendations for safe integration are identified, such as the need for a precharge circuit, crowbar circuit, and future short protection circuit. This study provides critical insight into the design and practical implementation of turbo-electric power systems for future electrified aircraft. [ABSTRACT FROM AUTHOR]

Small and midsize gas turbines for distributed power generation have been widely used in recent years, with designers constantly seeking to improve efficiency by increasing operating temperatures. Therefore, accurate thermal mapping is now more critical than ever for validating new designs, but also very challenging in such a dynamic environment as a gas turbine. A novel advanced offline temperature mapping technology has been developed called thermal history coating (THC). Thermal History technology has distinct advantages including wide temperature measurement range (150 °C to >1600 °C), high durability, high-temperature resolution, single or multicycle operation, high spatial resolution (thousands of measurement points per component), and fully digitized computer-aided design (CAD) compatible data. Additionally, THC materials are REACH-compliant and can be used for both moving and stationary components. High-resolution thermal maps of the surface of three-dimensional (3D) CAD components can be delivered at the end of the process. For the first time ever this paper directly compares Thermal History technology with other methods such as Type-K sheathed thermocouples, uniform crystal temperature sensors (UCTS), and pyrometry on two stage-1 blades of a midsize Kawasaki gas turbine engine test. Temperature data obtained from the different temperature methods were compared qualitatively and quantitatively. Measurement data were also compared with the conjugate heat transfer (CHT) model for the particular internal cooling design of these blades. Further, the application of the THC on two identical blades allowed a direct comparison of component-to-component variations and indicated excellent repeatability of the THC data. [ABSTRACT FROM AUTHOR]

This study explores the potential of hydrogen gas turbine engines for sustainable aviation, with a particular focus on their development for low subsonic to transonic flight regimes. Hydrogen offers notable advantages, including zero CO 2 emissions and high energy density. However, its widespread adoption is prevented by significant challenges in production, infrastructure, storage, aircraft design, and combustion technology. The limited availability of green hydrogen – the global production totaled only 127 kt in 2023, with 76% produced in China - raises concerns about the feasibility of a rapid shift to hydrogen-powered general aviation. Despite numerous pledges for hydrogen adoption in the Western world, major aircraft manufacturers have primarily engaged in marketing activities rather than substantial product innovation. To date, the only hydrogen aircraft demonstrator from this century is the 2012 Boeing Phantom Eye, which utilized modified hydrogen internal combustion engines rather than a gas turbine engine. The only hydrogen aircraft demonstrator with a gas turbine engine was the 1988 hybrid Tupolev Tu-155 which coupled one hydrogen gas turbine engine to other two jet fuel engines. This paper evaluates the current state of hydrogen gas turbine technology, comparing its combustion characteristics with traditional jet fuels and examining various NOx emission control techniques. It also investigates the potential of micro-mix lean combustion and staged combustion to achieve efficient and low-emission hydrogen combustion in gas turbines. Given the more extensive experience with terrestrial gas turbines compared to their aeronautical counterparts, the review includes insights from terrestrial power generation applications. Additionally, it considers hythane - a blend of hydrogen and natural gas - as a transitional solution for significantly reducing CO 2 emissions while progressing towards net-zero targets. The review underscores the urgent need for advancements in green hydrogen production, technology, and infrastructure to overcome existing barriers and enable a more sustainable aviation future powered by hydrogen. Importantly, the review emphasizes the need to move beyond mere virtue signaling and make tangible progress toward a hydrogen economy. [ABSTRACT FROM AUTHOR]

In this study, we used the numerical simulation tool FLUENT to numerically simulate the combustion of ammonia-hydrogen fuel in the combustion chamber of a 9E heavy-duty gas turbine, and analysed the effects of different hydrogen blending ratios on the stability of ammonia combustion and NOx emissions. We found that an increase in the hydrogen mixing ratio in the fuel during the ammonia-hydrogen mixture combustion process contributes to the reduction of NOx emissions and has a positive effect on combustion stability. The key highlights of our research include. (see Fig. 3–6 and 10 and 11) • Ammonia-hydrogen combustion simulation of the 9E heavy duty gas turbine. • Increase in the proportion of hydrogen leads to an increase in the maximum temperature produced by combustion. • The high temperature zone moves closer to the fuel inlet as hydrogen increases. • The increase in hydrogen has little effect on the flow field in the combustion chamber. • Increased hydrogen ratio effectively reduces NOx emissions. [ABSTRACT FROM AUTHOR]

Welding technologies represent a paramount joining process for ensuring the quality and reliability of critical industrial components; therefore, their innovation constitutes a driving force in realizing increasingly competitive products. A recently developed technology is the keyhole TIG welding, a new high energy–density alternative to the conventional TIG process. A key role in improving innovative manufacturing processes such as the keyhole TIG is covered by numerical simulation; indeed, it allows the development of a process digital twin able to support decisions and work as a predictive tool. Within this framework, the paper deals with the numerical-experimental investigation of the keyhole TIG technology, successfully employed on a simplified mock-up of an industrial gas turbine component consisting of two 6.5-mm-thick Inconel 718 rings. Numerical analysis aimed at predicting welding-induced distortions was performed employing two different computational approaches, namely the moving heat source and the simplified imposed thermal cycle methods. The numerical-experimental comparison of the results demonstrates an innovative approach in the field of the current keyhole TIG numerical simulation since, besides verification of numerical thermal analysis, further substantial validation of the post-weld distortion predictions is provided through comprehensive three-dimensional experimental data. Moreover, the comparative assessment of the two computational approaches and experimental evidence revealed that the imposed thermal cycle method implementation does not compromise the accuracy of welding distortion forecasting in industrial applications such as that investigated. Therefore, it can be regarded as a valuable tool for supporting the process engineer in designing the ideal set-up to comply with a variety of industrial requirements, among them strict design tolerances. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cells (SOFCs) play a critical role as a key technological component in the utilization of hydrogen energy. Extensive research has been conducted on pressurized SOFC hybrid systems, focusing on performance enhancement and novel system configurations, etc. However, the planar SOFC suitable for commercial application exists limitations that confine its operation solely to atmospheric pressure. Moreover, SOFC exhaust contained considerable potential for energy recovery. In light of these limitations, two hybrid power generation systems of SOFC and GT have been proposed: direct and indirect utilization of SOFC cycle exhaust. Parameter and exergy analysis has been conducted to investigate the characteristic of SOFC-GT system. Multi-objective optimization is performed by setting exergy efficiency and output power as objective. The results reveal that the combustion process contributes significantly to system losses, with exergy efficiency reaching a maximum of 49.48% and 41.61%, respectively. Additionally, the system's maximum output power reaches 92 kW. Notably, the indirect SOFC-GT system demonstrates an 8% increase in exergy efficiency compared to the direct SOFC-GT system at the same output power. To improve the overall system fire efficiency, it is recommended to develop planar SOFCs suitable for high pressure and slow down the reaction process inside the combustion chamber. • Two atmospheric pressure SOFC-GT systems are studied comparatively. • SOFC-IDGT configuration exhibits superior thermodynamic performance. • Multi-objective optimization is performed for this SOFC-GT system. [ABSTRACT FROM AUTHOR]

The ongoing transition to energy systems with high shares of variable renewables motivates the development of novel thermal power cycles that operate economically at low capacity factors to accommodate wind and solar intermittency. This study presents two recuperated power cycles with low capital costs for this market segment: (1) the near-isothermal hydrogen turbine (NIHT) concept, capable of achieving combined cycle efficiencies without a bottoming cycle through fuel combustion in the expansion path, and (2) the intercooled recuperated water-injected (IRWI) power cycle that employs conventional combustion technology at an efficiency cost of only 4% points. The economic assessment carried out in this work reveals that the proposed cycles increasingly outperform combined cycle benchmarks with and without CO2 capture as the plant capacity factor reduces below 50%. When the cost of fuel storage and delivery by pipelines is included in the evaluation, however, plants fired by hydrogen lose competitiveness relative to natural gas-fired plants due to the high fuel delivery costs caused by the low volumetric energy density of hydrogen. This important but uncertain cost component could erode the business case for future hydrogen-fired power plants, in which case the IRWI concept powered by natural gas emerges as a promising solution. [ABSTRACT FROM AUTHOR]

Modern heavy duty industrial gas turbines in combined cycle configuration, with rated efficiencies (at ISO base load) above 60% net LHV, are expected to play a significant role in reducing the carbon footprint of utility scale electricity generation. Even without postcombustion capture (PCC), simply switching from coal-fired generation to natural gas-fired generation reduces carbon dioxide emissions by 60% (on a kg per MWh of generation basis). In simple cycle mode, with efficiencies above 40% net LHV and startup times around 20 min, 300-400+ MW gas turbines can easily serve as peakers to support variable renewable resources, i.e., wind and solar. In this paper, a close quantitative look is taken at the capabilities of gas turbines firing natural gas, hydrogen, or a blend thereof, both in simple and combined cycle configurations. Furthermore, using published data, first-principles calculations, and software simulations, it will be shown that the gas turbine constitutes an efficient and cost-effective technology, with and without carbon capture, as a key player in decarbonization of the electric power sector. [ABSTRACT FROM AUTHOR]

This research study entails the determination of the due time required for carrying out hot gas path inspection of a gas turbine. Delay in execution of HGPI may result in machine failure, extra cost and loss in revenue while early execution may result in unnecessary cost, waste, and loss in revenue due to downtime. Hence, the aim of the research study, to model and evaluate the due time for carrying out hot gas path inspection for a GE frame 9E machine. This study was conducted using GT17 of Transcorp Power Limited, Ughelli, Delta State. The methodological approach considered for this study was to carry out a mathematical modelling approach in determining the due time for carrying out HGPI. A corrosion rate formula was developed, presented and used in the modelling process. The two main parts considered for the experiment were turbine buckets and shroud blocks, which is considered critical for the turbine clearance when undertaking HGPI. Based on the mathematical modelling analysis, the due time for the turbine buckets were 24134.9hrs for stage 1, 235456hrs for stage 2 and 24727.5hrs for stage 3. In correspondence, turbine shroud blocks due time were computed at 24805.3hrs, 24497.8hrs and 23346.1hrs for stages 1, 2 and 3 respectively. Based on the efficiency computed, it was discovered that the efficiency of the gas turbine reduces gradually until maintenance activities are carried out to improve the efficiency, reliability and availability of the gas turbine. [ABSTRACT FROM AUTHOR]

The curvic coupling, as one of the common connecting structures for gas turbine combined rotors, is more susceptible to various dynamic and static loads at extreme operating conditions. But, traditional combined rotor models tend to neglect the influence of the connection structure, especially failing to consider the contribution of the curvic coupling interfaces. To address this problem, this paper establishes a solid geometric model of the combined rotor with curvic couplings considering the rough three-dimensional interfaces. The effectiveness of the proposed model method is indirectly verified through the compression tests and modal tests. Subsequently, combined with finite element calculations, the mechanical properties of the rotor with curvic couplings considering the rough interface are analyzed under static and dynamic load conditions. The results indicate that the roughness of the interface significantly affects the deformation of the contact surface under static load, but its impact on the overall deformation of the rotor is relatively insignificant. The dynamic stress at the interface exhibits periodic variations at the resonance speed. At the maximum operating speed, the dynamic stress is influenced by the magnitude of imbalance. The aforementioned methods and conclusions provide a reference for the design research and engineering application of combined rotors. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Xi'an Jiaotong University is the property of Editorial Office of Journal of Xi'an Jiaotong University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Six significant biomasses were examined in this communication to determine their respective thermodynamic performances. To recover the waste heat extracted from the HRSG, the proposed system integrates a gas turbine, a steam turbine, and a vapour absorption at the bottom. The investigation's sole goal is to determine how well thermodynamic processes perform from an energy, exergy, and environmental standpoint. The results reveal a clear trend wherein the increase in turbine inlet temperature from 1273 to 1473 K leads to a concurrent rise in both energy and exergy efficiencies. Additionally, apple bagasse material has the lowest energy and exergy efficiencies compared to solid waste material, which has the best thermodynamic performance of about (37.6% and 35.9%). Additionally, the combustion chamber (apple bagasse) is noted to have the highest exergy destruction at about 32.1%, followed by the HRSG and gasifier at about 16.3% and 11.3%, respectively. [ABSTRACT FROM AUTHOR]

A Gas Turbine (GT) is a combustion engine that converts fuel into mechanical energy. None of the conventional models has utilized the stator hub, rotor tip leakage, and inter-stage flow for the optimum design of GT. This study performs an effective design parameter analysis for GT with heat transfer rate and fluid flow detection using Betadecay with cloglog-based Long Short-Term Memory (Beta-clog²-LSTM) and Griewank Siberian Tiger Optimization (G-STO). Initially, the design parameters were taken and the geometry of those parameters was created. Afterward, mesh generation was performed using the Linear Weighted Gradient Smoothing Sliding Mesh Interface (LWGSSMI). Then, the boundaries of the generated mesh were detected. Next, numeric modeling was performed deploying Finite Element Analysis (FEA), followed by flow behavior analysis. The optimal parameters were selected by G-STO. Similarly, the data in a heat transfer rate dataset were preprocessed and the features were extracted. Prediction of heat rate was performed using Beta-clog²-LSTM. Finally, the thermal loss was calculated, and a heat exchanger was utilized to mitigate it. The performance analysis demonstrated the robustness of the proposed method by achieving 0.98 prediction accuracy. [ABSTRACT FROM AUTHOR]

To achieve higher thermal efficiency in a gas turbine, increasing the turbine inlet temperature is necessary. The rotor blade at the first stage tolerates the highest temperature, and the serpentine internal channel located in the middle chord of the rotor blade is vital in guaranteeing the blade's service life. Therefore, it is essential to illustrate the evolution of the rotating internal channel in a gas turbine blade. In the paper, the influence of the Coriolis force, including its mechanisms, on the conventional rotating channel are reviewed and analyzed. A way to utilize the positive heat transfer effect of the Coriolis force is proposed. Recent investigations on corresponding novel rotating channels with a channel orientation angle of 90° (called bilaterally enhanced U-channels) are illustrated. Moreover, numerical investigations about the Re effects on bilaterally enhanced smooth U-channels were carried out in the study. The results indicated that bilaterally enhanced U-channels can utilize the Coriolis force positive heat transfer effect on the leading and the trailing walls at the same time. Re and Ro are vital non-dimensional numbers that influence the performance of bilaterally enhanced U-channels. Re and Ro have an independent influence on the heat transfer performance of the bilaterally enhanced U-channel. Ro is good for the heat transfer of the bilaterally enhanced U-channel on both the leading and the trailing walls. Therefore, the bilaterally enhanced U-channel is suitable for application in the middle chord region of a turbine blade, since it can utilize the rotation effect of the rotating blade to improve the heat transfer ability of the blade and thus reduced the blade temperature. At the same Ro, Re positively affects the Nu on the leading and the trailing walls of the Coriolis-utilization rotating smooth U-channel, but plays a negligible role on Nu/Nu0. [ABSTRACT FROM AUTHOR]

Manufacturing of thermal barrier coatings (TBCs) with optimization is one way that can be adopted to mitigate the negative impact of the aviation sector on the natural environment in its near surroundings. TBCs derived from germinates are contenders for meeting the present market need for coatings that fulfill the severe requirements of tomorrow's gas turbines (GT) engines for industrial and commercial aircraft use age. To curb the issues related to emissions, researchers have continuously working on developing the coatings for jet engines parts so as to achieve maximum efficiency out of it. Plasma coating has been utilised in a variety of industrial and aerospace applications due to its improved high-temperature oxidation performance of coated objects. The manufacturing approach of TBCs leads to sustainable approach by lowering the emissions. The Yttria-stabilized zirconia (YSZ) based coatings were sprayed using a plasma spray technique in this work, with the metal substrates (SS-304) serving as the spray target. The purpose of this experimental investigation was to investigate the application of atmospheric plasma spray (APS) in order to coat an SS-304 substrate with a composite consisting of YSZ, Al2O3, and CeO2. It was noticed that coatings had been produced in a manner that was uniform across the surface of the substrate. The purpose of this research was to gain a better understanding of the qualities of YSZ/Al2O3/CeO2 plasma sprayed coatings by characterising the surface of the coatings. The developed coatings were compared with the existing coatings to understand the newly developed coatings. [ABSTRACT FROM AUTHOR]

This article numerically explores the effects of the film hole diameter on the performance of the film and vortex composite cooling. The vortex cooling structure is set in the leading edge of a GE E3 airfoil, connecting with the mainstream flow by the film holes and the blade material to achieve mass transfer and heat transfer, respectively. Five cooling structures with the film diameter d equal to 0.12 mm, 0.20 mm, 0.28 mm, 0.36 mm, and 0.44 mm are involved. Simulations are carried out under the rotating speed of 0 rpm, 1000 rpm, 2000 rpm, 2500 rpm, and 3000 rpm for all structures. The dimensionless temperature θ of the blade leading edge surface is defined to evaluate the cooling performance. The higher θ represents the lower temperature. Results show the different rotational effects on the different structures. First, the value of θ increases with the increasing film hole diameter under the same rotating speed. The value of θ in the case of 0.44 mm is around 5 times that in the case of 0.12 mm. Second, the peak value of θ is observed under the rotating speed higher than 2500 rpm when d is lower than 0.28 mm. While the peak value of θ is observed under 1000 rpm when d is higher or equal to 0.28 mm. The peak value of θ represents an increase of 11.23% and 2.76%, as compared to the lowest value of θ when d is equal to 0.12 mm and 0.44 mm, respectively. Because the dominating cooling methods are different in the cases with different film hole diameters. [ABSTRACT FROM AUTHOR]

This study analyzes the turbomachinery flow of a gas turbine using OpenFOAM, an open-source CFD code. While foam-extend, a version of OpenFOAM, includes tools for turbomachinery analysis, some of its codes are incomplete, resulting in incorrect results. Consequently, this study required the investigation and correction of the solvers and libraries. Specifically, foam-extend-4.1 and a compressible multi-reference-frame solver were utilized. Two primary errors related to temperature calculation were identified. The first error involved temperature discontinuity at the interface between the stator and rotor domain when using the mixingPlane. The second error was related to temperature rising at the wall. To address the temperature discontinuity problem, the rothalpy jump equation in the enthalpyJump code was modified from a scalar product to an inner product of vectors. To resolve the high-temperature problem at the wall, modifications were made to the energy equation code in iEqn.H. A rothalpy separation was introduced, and the rothalpy equation was adjusted to mimic the enthalpy equation. The results obtained with the corrected codes were consistent with those from the commercial code, demonstrating the effectiveness of the modifications. [ABSTRACT FROM AUTHOR]

At COP26, Vietnam committed to achieve net zero emissions by 2050. Up to now, several strategic policies and master plans concerning energy and power development along with emission reduction have been introduced. The national power development plan for the 2021-2030 vision to 2050 (PDP8) has directed for gas-to-hydrogen fuel conversion at gas turbine power sources in the national power system when the technology is commercialized and the cost is appropriate. Therefore, gas turbine power plants (GTPPs) with a total capacity of approximately 32.4 GW by 2050, using domestic natural gas and imported liquefied natural gas (LNG), will be expected to switch to using green hydrogen (GH2) to cut greenhouse gas (GHGs) emissions. This study uses the SWOT analysis and analytic hierarchy process (AHP) method to quantitatively analyze and examine the factors influencing the perspective of GH2 conversion at CTPPs in Vietnam. Research results show that among the four groups of Strengths, Weaknesses, Opportunities, and Threats being examined, the most influencing one is Weaknesses with the highest weight of 0.381, followed by Threats (0.343), suggesting that the GH2 conversion ambition will be facing significant challenges and difficulties. At the level of element factors in the groups, the lack of infrastructure and insufficient legal framework/specific incentive mechanisms are the biggest weaknesses, with weights of 0.362 and 0.326, respectively, while the consistent policies of the state and abundant potential of renewable energy resources, weighing 0.446 and 0.235, respectively, are Vietnam's prominent strengths. Additionally, remarkable opportunities include the effective exploitation of available renewable energy resources (0.338) and great contribution to reducing emissions (0.288), while the main challenges remain the lack of capital (0.471) and high GH2 cost (0.284). The research results clarify the typical problems of a developing country like Vietnam in the global energy transition trend toward carbon neutrality: high potential of renewable energy sources, great political determination, and ambitious goals for green growth, but significant difficulties and challenges due to the low starting point and limited technological and financial resources while energy demand is constantly increasing. Thus, some strategic solutions are proposed, including taking advantage of internal strengths to avoid/limit external threats, making the most of strengths to exploit opportunities, and minimizing weaknesses to take advantage of opportunities and to limit the threats. [ABSTRACT FROM AUTHOR]

In gas‐fired power plants, emissions may reduce turbine blade rotation, thus decreasing power output. This study proposes a hybrid model integrating the Feed forward Neural Network (FFNN) model and Particle Swarm Optimization (PSO) algorithm to predict gas emissions from natural gas power plants. The FFNN predicts gas turbine nitrogen oxides (NOx) and carbon monoxide (CO) emissions, while the PSO optimizes FFNN weights, improving prediction accuracy. The PSO adopts a unique random number selection strategy, incorporating the K‐Nearest Neighbor (KNN) algorithm to reduce prediction errors. Neighbor Component Analysis (NCA) selects parameters most correlated with CO and NOx emissions. The hybrid model is constructed, trained, and testedusing publicly available datasets, evaluating performance with statistical metrics like Mean Square Error (MSE), Mean Absolute Error (MAE), and Root Mean Square Error (RMSE). Results show significant improvement in FFNN training with the PSO algorithm, boosting CO and NOx prediction accuracy by 99.18% and 82.11%, respectively. The model achieves the lowest MSE, MAE, and RMSE values for CO and NOx emissions. Overall, the hybrid model achieves high prediction accuracy, particularly with optimized PSO parameter selection using seed random generators. [ABSTRACT FROM AUTHOR]

There is an enormous amount of water vapor in ambient air that can be converted into liquid water by several methods. A method that is capable of producing a large amount of water is a vapor compression system. However, this method requires significant power input, which may cause the cost of producing water to be prohibitive. In this paper, it is proposed that a vapor compression refrigeration system that is used to cool air in a combined cycle power plant has the potential to be a viable method of atmospheric water generation. This system produces saturated air by mixing atmospheric air with water, and reduces air temperature and humidity using a mechanical chiller. The reduction in inlet air temperature enables the combined cycle power plant to generate more power output, which is used to operate the air cooling system. Therefore, the air cooling system can harvest atmospheric water without requiring external power input. This concept is proven by simulating system performance in various atmospheric air conditions using system models of mass and energy balances. [ABSTRACT FROM AUTHOR]

Over the years, airlines have consistently attempted to lower their operational costs and improve aircraft availability by applying various technologies. Engine maintenance expenses are one of the most substantial costs for aircraft operations, accounting for around 30% of overall aircraft operational costs. So, maximizing aircraft time between overhaul (TBO) is crucial to lowering the costs. The engine time on-wing is often limited due to the expiration of Life Limiting Parts, performance deterioration, etc. This paper presents a novel method of rebalancing the thrust of engines of an aircraft to maximize the time between overhaul of the aircraft considering the performance degradation and creep life consumption of the engines. The method is applied to a model aircraft fitted with two model engines similar to GE90-115B to test the feasibility of the method with one engine degraded and the other engine undergraded. The obtained results demonstrate that for the aircraft flying between London and Toronto with 5000 nominal flight cycles given to the engines, the time on-wing of the degraded engine could drop from 5000 to 2460 flight days due to its high-pressure (HP) turbine degradation (1% efficiency degradation and 3% flow capacity degradation), causing the same level of drop of time between overhaul of the aircraft. The time on-wing of the degraded engine could increase from 2460 flight days without thrust rebalance to 3410 flight days with thrust rebalance, i. e. around 38.6% potential improvement for the time between overhaul of the aircraft at the expenses of increased creep life consumption rate of the clean engine. The proposed method could be applied to other aircraft and engines. [ABSTRACT FROM AUTHOR]

The flame stability limit and propagation characteristics of a reverse-flow combustor without any flame-stabilized device were experimentally investigated under room temperature and pressure. The results indicate that it is feasible to stabilize the flame in the recirculation zones constructed by the impact jet flow from the primary holes and dilution holes. The flame projected area is mainly distributed in the recirculation zone upstream of the primary holes, whose presence and absence mark the ignition and extinction. During the ignition process, the growth rate and value of the flame projected area first increase and then decrease with the inlet velocity increasing from 9.4 m/s to 42.1 m/s. A rapid reduction followed by a slow reduction of ignition and lean blowout equivalence ratios is achieved by the increased inlet velocity. Then the non-reacting fluid structure in three sections was measured, and detailed velocity profiles were analyzed to improve the understanding of the flame stabilization mechanism. The results are conducive to the design of an ultra-compact combustor. [ABSTRACT FROM AUTHOR]

This paper presents an analysis of factors causing the change in the real gage factor of high-temperature strain gages installed with ceramic cements. A calibration tool to mimic the load on the strain gage during the testing of gas turbines and to determine the real gage factor is described. Calibration data obtained for two samples of nickel–chromium strain gages and two samples of iron–chromium–aluminum strain gages are given and analyzed. [ABSTRACT FROM AUTHOR]

Gas turbine engines have several advantages over piston reciprocating engines, such as higher output per unit volume, reduced vibration, rapid acceleration and deceleration, high power output, and clean exhaust gases. As a result, their use for propulsion in ships has been steadily increasing. However, gas turbine engines exhibit significant parameter variations depending on the rotational speed, making the design of controllers to ensure system stability while achieving satisfactory control performance, a very challenging task. In this paper, a novel CEM-based 2-DOF PID controller design technique is proposed to ensure the stability of a gas turbine engine while improving tracking and disturbance rejection performance. The proposed controller consists of a PID controller focused on enhancing disturbance rejection performance and a set-point filter to improve tracking performance. The set-point filter is composed of gains from the controller and a single weighting factor. When tuning the gains of the controller, the maximum sensitivity is considered to maintain an appropriate balance between system stability and response performance. The key novelty of this study can be summarized in two main points. One is that the controller is designed by matching characteristic equations, and by setting the roots of the desired characteristic equation as multipoles, the gains of the PID controller can be tuned with only one adjusting variable, making the tuning of the 2-DOF controller easier. The other is that the controller parameters are tuned based on maximum sensitivity, thus taking into account the robust stability of the control system. To demonstrate the feasibility of the proposed method, simulations are conducted for four scenarios using various performance indices. [ABSTRACT FROM AUTHOR]

This paper presents an investigation into the influence of Y-La and Y-Hf-La modifiers on the structure and properties of Ni-Cr-Al consumable cathodes used for heat-resistant coatings on turbine blades via the arc-ion plating method. The study shows that the introduction of these modifiers positively affects the structure formation process of the consumable cathodes. The modifiers contribute to a higher degree of microstructural homogeneity in the cathodes, achieved through the formation of nanosized stabilizing phases between the alloying elements and the rare earth metal groups. This study experimentally confirms that Ni-Cr-Al coatings produced with the Y-La and Y-Hf-La modified cathodes outperform traditional Y-only modified coatings in oxidation tests. Structural analysis of the coatings reveals that samples with Y-Hf-La exhibit greater homogeneity and fewer defects, which is particularly important when depositing coatings with large thicknesses (over 40 µm). It was found that the introduction of the Y-Hf-La complex enables the application of coatings up to 90 µm thick by forming a less defective structure. Additionally, it has been established that Y-Hf-La modification enhances the adhesion of the coating to the substrate and allows for maximum uniformity in the distribution of alloying elements throughout the entire thickness of the applied coating. [ABSTRACT FROM AUTHOR]

In accordance with the requirements of power systems to power units of thermal power plants, there are different approaches to variable modes of their operation, duration of start-ups from different thermal states, regulating rates of equipment loading during start-ups and load changes. A considerable role at performance of start-up operations is assigned to supply of heat recovery steam generator (HRSG) circuits that provide the change of HRSG steam capacity corresponding to the loading rate while maintaining all main parameters within the permissible limits. Besides, optimization of duration of CCPP start-up modes should take into account accumulation of damage by the most loaded thick-walled elements of steam path equipment. This occurs due to continuous monitoring of thermal stress state and cyclic strength of CCPP elements under conditions of minimum resource consumption on the basis of finite element mathematical models of critical elements of steam path and calculation studies of thermal stresses arising in them. The influence of HRSG steam capacity on CCPP power change rate under different schemes of high, medium and low-pressure steam circuits supply (HP,MP, LP) has been analyzed. It is shown that the least inertial are deaeratorless schemes with a separate electric feed pump (EFP) of HP, which allows to provide fast, at the pace of the process, change of steam capacity of the HP circuit at any alternating mode, including starts and stops. [ABSTRACT FROM AUTHOR]

The paper discusses the aspects of implementation of high-precision digital twins for power plants and energy systems based on the approaches used by General Electric (GE), which has an extensive experience in this field. To create such twins, the company uses laws of physics, knowledge and experience in engineering design, methods of measuring and controlling various parameters, as well as artificial intelligence technologies. The paper offers a description of models, methods, and approaches used by GE when developing digital twins. The company's experience in the use of artificial intelligence technologies, such as pattern recognition, unstructured (multimodal) data analysis, and expert networks, as well as sensor technologies is presented. The most important component of GE's digital twin is the Predix simulation platform. It was specifically developed by GE by using industrial Internet technologies to perform analytical processing of huge amounts of machine data in real time. The basic capabilities and specifications of the Predix platform are provided. [ABSTRACT FROM AUTHOR]

This paper presents a pioneering investigation into an integrated power generation cycle that combines gas turbines, steam turbines, Goswami cycles, biomass fuel, solar energy sources, and advanced Maisotsenko heat exchangers. Biomass gasification has been applied to partially fuel the gas turbine, while the M‐Cycle serves as the gas turbine inlet air cooling system. Solar parabolic collectors are utilized to elevate the compressed air temperature for combustion, and the Goswami cycle generates both power and cooling through waste heat recovery. This research addresses a critical gap by undertaking a holistic examination of the integrated power generation cycle, modelling the overall system performance by considering interactions and synergies between various components. The base model has been implemented, and the impacts of influential parameters on system efficiency, such as ambient temperature, seasonal variation, and steam‐to‐biomass ratio, have been taken into consideration. Remarkably, the incorporation of the M‐Cycle, solar parabolic systems, steam cycles, and the Goswami cycle into the base gas cycle results in substantial energy efficiency enhancements of 1.59%, 1.96%, 16.87%, and 6.06%, respectively, highlighting the transformative potential of this integrated approach for sustainable and efficient power generation. [ABSTRACT FROM AUTHOR]

The exergy‐based sustainability indices have been a cause of concern for gas turbine power plant as its performance is very sensitive to air temperature. Hence, the present study evaluates the impact of atmospheric air temperature on exergy sustainability and ecological function of a naphtha‐based gas turbine power plant using EES. The outcome of the study shows that combustion chamber (CC_1) needs more attention compared with other components present, and it has least improvement potential as compared with other components. Further while carrying out parametric analysis with respect to ambient air, it was observed that for a 1.1°C increase in atmospheric air temperature a reduction in sustainability index about 0.66% was observed respectively, for GT_1. Thus, this study established that the power plant's exergy sustainability performance has a negative impact at high ambient air temperatures on exergy sustainability indices. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ObjectivesWith the implementation of the national “Dual Carbon Strategy” (carbon peak and carbon neutrality), it is anticipated that the existing coating structures may not meet the requirements of future gas turbine thermal protection coatings. The concept of a new type of environmental/thermal barrier coating (E/TBC) structure with high temperature corrosion resistance has been proposed to meet the demand for thermal protection coatings in hybrid hydrogen combustion engines.MethodsThe development history and research status of thermal barrier coating (TBC), environmental barrier coating (EBC), thermal/environmental barrier coating (T/EBC) and thermal and environmental barrier coating (TEBC) were reviewed and analyzed from the perspective of thermal protection coating materials and coating structures. Moreover, the gap between the above coating structures and the requirementsof thermal protection coating for mixed hydrogen gas turbines was investigated.ResultsIt is reasonable to superimpose the function of EBC onto the thermal protection coating of current mixed hydrogen gas turbines, thereby forming a new type of E/TBC structure with high temperature corrosion resistance on the high-temperature alloy substrate.ConclusionsThrough the preliminary test, it is proved that the new E/TBC structure is suitable for the thermal protection coating requirements of mixed hydrogen gas turbine against high temperature water oxygen corrosion, and it is pointed out that the theory and application research of this new E/TBC thermal protection coating should be vigorously carried out.

ObjectivesThe operating state under the condition of high-pressure turbine damage will have a certain impact on the performance and vibration of the gas turbine. At present, the means to accurately assess whether the whole machine can continue to be in service was relatively lacking. Therefore, the research on the influence of the tip groove wear and block shedding of the high-pressure turbine rotor blade on the aerodynamic performance and vibration deformation had been carried out.MethodsUsing the three-dimensional numerical simulation method, based on the original tip groove structure of the blade, the influence of five different tip groove damage shapes on typical aerodynamic performance and vibration characteristics of the high pressure turbine was simulated and analyzed.ResultsThe damage of the blade tip groove on the pressure side with falling block, suction side with falling block, trailing edge with falling block, pressure side and trailing edge with falling blocks simultaneous, or pressure side, suction side and trailing edge with falling blocks simultaneous of rotor blades cause an efficiency decrease of 0.44%, 1.6%, 0.03%, 0.67%, and 3.2%, respectively. Different blade squealer tip shapes have a smaller impact on the vibration deformation of the rotor blade, while trailing edge with falling block reduces the deformation of the rotor blade.ConclusionsBased on the analysis results of comprehensive performance and vibration, rotor blades with falling blocks at pressure side, trailing edge, or both can continue to be used. However, it is not recommended to use rotor blades with falling blocks at suction side or pressure side, suction side and trailing edge.

ObjectivesThe effectiveness of cooling technology directly influences the performance and lifespan of gas turbine blades operating in high-temperature, and high-pressure environments. The research status of swirl cooling technology was reviewed, aiming to summarize and evaluate its application in enhancing cooling efficiency and reducing thermal stress, and systematically analyze the basic principle and performance of swirl cooling technology.MethodsThe review focused on the design of swirl cooling channels, the combined use of swirl and film cooling, and the impact of rotational conditions on heat transfer performance.ResultsThe swirl cooling technology significantly improves blade cooling efficiency and reduces thermal stress concentration. Specifically, reasonable design of swirl cooling channel can achieve uniform distribution of cooling fluid, enhance the cooling effect and prolong the service life of the blade.ConclusionsThe application of swirl cooling technology in gas turbine blade cooling has broad prospects. Future research should continue to explore the optimized design of swirl cooling technology and its performance under various operating conditions. Additionally, the combination with advanced manufacturing technologies, such as additive manufacturing, can further enhance the design complexity and cooling efficiency of swirl cooling channels, providing reliable support for the efficient and stable operation of gas turbines.

ObjectivesThe high-efficiency internal cooling technology of turbine blade is crucial for improving the thermal efficiency of gas turbine. As an important component of the gas turbine, it is essential to conduct research on the cooling performance of rotor blade. Due to significant effect of Coriolis force, buoyancy force, and channel structure on the cooling performance of rotating internal channel of turbine blade, this paper summarized the research status and development trends of rotating internal cooling channel based on these effect factors.MethodsA new structural design of rotating internal cooling channels was introduced, and a new rotating internal cooling channel structure suitable for double-walled blade configurations was proposed.ConclusionsDouble-sided enhanced U-shaped channels can utilize the enhanced heat transfer effect of Coriolis force, resulting in better cooling performance than traditional rotating U-shaped channels. There is a broad room for improvement in the internal cooling of gas turbine rotor blades.

ObjectivesThe inlet temperature of gas turbine has far exceeded the allowable temperature of the blade material, so it is very important to develop more efficient turbine cooling technology, especially the film cooling technology. The film cooling in the central region of the turbine blade is usually supplied by the crossflow ribbed passage. Therefore, the research progress of the film cooling in the crossflow ribbed passage in recent years was reviewed.MethodsThe variations in film cooling performance under different coolant supply modes were introduced. The impacts of rib angle, rib shape, relative position of film holes and ribs, and Reynolds number at the inlet of the crossflow channel on flow and film cooling performance were summarized. The research progress of film cooling hole shape design under the condition of crossflow ribbed cooling air was concluded.ResultsThe internal cooling structures within the crossflow ribbed passage and the Reynolds number at the entrance of the crossflow channel exert significant influences on film cooling performance, while the distribution of cooling effectiveness at the hole outlet downstream is altered during crossflow intake. Moreover, the flow at the hole entrance is influenced by both the relative position of the hole and rib as well as changes in Reynolds number. The asymmetrical spanwise cooling hole and the hole insensitive to the crossflow can enhance the film cooling performance.ConclusionsIn order to further promote the development of film cooling technology in the crossflow ribbed passage, it is recommended to thoroughly study the relationship between film cooling performance and all influencing factors, and to optimize the design of special film cooling hole suitable for crossflow ribbed inlet.

ObjectivesThe localization of core components of heavy-duty gas turbines holds significant importance for technological innovation, industrial upgrading, and even national security. As a typical hot-end component of heavy-duty gas turbines, the performance of the turbine first-stage rotor blade directly determines the efficiency and reliability of the gas turbine. Therefore, the structure of the first-stage turbine blades of a certain heavy-duty gas turbine was optimized.MethodsBy increasing the number of bamboo nodes in the blade body, the blade cooling hole structure was optimized, and the thermal barrier coating was used to improve the blade coating. The temperature, stress distribution and aerodynamic efficiency of the blades before and after optimization under the service condition of the blade were compared and analyzed by fluid calculation and finite element calculation.ResultsHeat transfer efficiency inside the blade is enhanced by optimization of turbulent structure. Under the condition of the same inlet pressure of the cooling air, the surface temperature of the optimized blade is reduced by more than 50 ℃. Since the shape of the blade is not changed, there is little influence on the aerodynamic efficiency. Compared with the blades without optimization, the maximum equivalent stress and equivalent total strain of the optimized blade during service are significantly reduced.ConclusionsBy optimizing the cooling structure and upgrading the protective coatings, the reliability of the blades in high-temperature can be significantly improved. The research results provide a theoretical basis for the localization of gas turbines.

The increase in size and efficiency of gas turbines leads to higher temperature in the combustion chamber, putting greater demands on the performance of the thermal insulation tiles. Corundum–mullite has been used because of its high‐temperature resistance, thermal shock resistance, and low thermal conductivity. However, how to inhibit heat transfer through composition regulation while ensuring the safe use of high‐temperature insulation tiles is the key to improving the heat conversion efficiency of gas turbines. In this study, thermal insulation tiles were prepared by casting molding. On the basis of determining the optimal corundum/mullite ratio (22:45 wt%) in the aggregate, the thermal conductivity of the sample was reduced by adding MgO (2 wt%). The results show that phonon intrinsic and defect scattering, caused by changes in phase composition, effectively reduce the thermal conductivity of the insulation tile sample to 2.05 W·m−1·K−1, which is 34.71 % lower than the maximum value before regulation. During 30 cycles of thermal shock (air‐cooling at 1000°C), the residual strength gradually decreased and tended to be stable, with a minimum of 8.6 MPa, indicating that the thermal insulation tile can provide better thermal insulation without affecting the safety of gas turbines, providing new ideas and methods for improving the thermal insulation performance of high‐temperature thermal insulation materials. [ABSTRACT FROM AUTHOR]

The article presents the results of theoretical studies of the ignition process of a water-coal fuel particle under conditions of high-temperature heating at high pressures of the external environment. The authors have developed a new mathematical model of the water-coal fuel particles ignition under stress (pressure – Pg = 1–200 bar, and temperature Tg = 873–1273 K) heating conditions. The mathematical model differs from the known ones by a detailed description of the physicochemical processes occurring during the induction period of time, as well as the processes of phase transitions under high pressure conditions. Based on the results of numerical simulation of the ignition process, it was found that the pressure of the external environment (Pg) has a significant effect on the characteristics and conditions of ignition of water-coal fuel particles. It was shown that the tign(Pg) dependence is essentially nonmonotonic. The authors have established that when Pg changes in the range from 1 to 30 bar (for oxidizer temperatures (Tg = 873–1273 K), an increase in the ambient pressure leads to a nonmonotonic increase in tign. In this way such a dependence tign(Pg) is due to the joint influence of two significant parameters of the factor space, which significantly affects the dynamics of the thermal treatment of fuel. With an increase in the pressure of the mixture of oxidizer and combustible gases, the saturation temperature (the temperature of intense evaporation of water) increases, at the same time, the heat of the phase transition (QL) decreases and the rate of release of pyrolysis gases into the oxidizing environment decreases. Based on the results of the theoretical studies, it has been shown that for efficient combustion of water-coal fuel under the conditions of the combustion chambers of a GT at oxidizer temperatures Tg≥1073K, the pressure in the combustion chamber of the GT must be at least 50 bar. [ABSTRACT FROM AUTHOR]

ObjectivesWith the annual increase in the generation of solid waste, traditional treatment methods have struggled to meet the increasingly stringent environmental requirements and the demands for resource recycling. In order to realize the efficient utilization of solid waste resources, a combined medical waste-waste tire resource utilization system based on gasification and pyrolysis was proposed.MethodsThe system fully combined the advantages of plasma gasification and pyrolysis technologies, coupling the medical waste plasma gasification power generation technology with tire pyrolysis technology. The syngas obtained from the gasification and pyrolysis processes was utilized together as the fuel of a gas turbine. At the same time, the high-temperature flue gas produced by the gas turbine provided the heat source for tire pyrolysis, after which the flue gas heat was recovered by a waste heat boiler. While harmlessly treating the medical waste-waste tires, the gradient utilization of energy was realized. The energy analysis and economic analysis of the proposed system were carried out under the condition of fixed feed rate.ResultsThe system is able to achieve a total energy output of 23.59 MW, with a total energy utilization efficiency of 52.56%, which is much higher than the efficiency of conventional waste-to-energy generation. The system has good economic returns, and can realize a relative net present value of 727.978 1 million yuan in a 20-year life cycle, and the dynamic payback cycle is only 3.13 years.ConclusionsThe research results provide a new technical path for the efficient co-processing of solid waste resources.

There is an enormous amount of water vapor in ambient air that can be converted into liquid water by several methods. A method that is capable of producing a large amount of water is a vapor compression system. However, this method requires significant power input, which may cause the cost of producing water to be prohibitive. In this paper, it is proposed that a vapor compression refrigeration system that is used to cool air in a combined cycle power plant has the potential to be a viable method of atmospheric water generation. This system produces saturated air by mixing atmospheric air with water, and reduces air temperature and humidity using a mechanical chiller. The reduction in inlet air temperature enables the combined cycle power plant to generate more power output, which is used to operate the air cooling system. Therefore, the air cooling system can harvest atmospheric water without requiring external power input. This concept is proven by simulating system performance in various atmospheric air conditions using system models of mass and energy balances.

[Introduction] With the development of "3060" double carbon target, the usage of the PV and wind power for hydrogen gas production is becoming a hot and cutting-edge direction. The combustion of natural gas mixed with hydrogen gas in gas turbine of hydrogen gas industry will become the final step to convert hydrogen into electric power. The gas turbine unit have pressure regulation station, front module and connection pipe. The front module have requirements on the flow rate, pressure, temperature and particle content. And the pressure regulation station will provide the required mixed gas to front module. The connection pipe will have a length of 1 000 m which depended on the different arrangement. The character of pressure drop and temperature drop of connection pipe will have direct impact on the interface parameter of pressure regulation station. So it is necessary to study the character of pressure drop and temperature drop of connection pipe. And it will provide a practicable solution for the future gas turbine fired with natural gas mixed with hydrogen gas. [Method] The fuel demand was given for the H class gas turbine fired with mixture of natural gas and hydrogen gas after the simulation calculation with GT Pro software. The recommended material selection and velocity selection were presented based on required temperature and pressure drop by H class gas turbine front module and the physical character of mixed gas. The pipe pressure drop and temperature drop due to pressure drop were also calculated. [Result] The pipe material selection, diameter selection, pipe pressure drop and temperature drop due to pressure drop of pipe are presented. [Conclusion] For present time, the pipe design between natural gas pressure regulation station and gas turbine front module shall evaluate the material, outer diameter, wall thickness, velocity, pipe resistance, etc., each by each under the condition with hydrogen gas mixture. Thus the gas turbine can use natural gas at present phase and can be shifted to combustion with mixed hydrogen gas smoothly.

In this study, three premixed swirl gas turbine nozzles with different fuel injection hole sizes were designed to optimize combustion characteristics influenced by changes in the hydrogen mixing ratio. Experiments involved increasing the hydrogen volume fraction of the fuel from 0 to 60%. The amount of fuel supplied through the pilot flow was increased to suppress combustion instability. The OH* chemiluminescence technique was introduced to analyze flame structure. To understand combustion instability, time delay and time-delay distribution were derived from flame structure analysis and applied to the 1D thermoacoustic model. The results indicated that the amount of fuel required for pilot injection with increasing hydrogen ratio varied with fuel hole size. It was also observed that changes in fuel hole size significantly affected flame characteristic length. Findings from the 1D thermoacoustic analysis confirmed that fuel hole size variation altered combustion instability characteristics by influencing time delay and time-delay distribution variation. [Display omitted] • This study investigated the impact of fuel hole size for H 2 co-firing. • Increase in H 2 fraction reduced flame length and heat release distribution. • Fuel hole size variation affected time delay and its distribution. • Changing the time delay and its distribution influenced combustion instability. [ABSTRACT FROM AUTHOR]

The consideration of aeroelasticity is essential during the development phase of axial flow compressors, and its implications should be factored into the operational planning of gas turbines. While synchronous vibration can typically be mitigated during the blade design stage, the complete avoidance of non-synchronous vibration remains a challenge, prompting ongoing research efforts for predictive solutions. The study utilized an industrial gas turbine axial compressor with 1.5-stage blades for aerodynamic performance and flutter assessments. The calculated results were comprehensively compared with those of 1.5-stage scaled rig test. The comparative analysis demonstrated a strong alignment between predictions regarding aerodynamic performance and the presence or absence of flutter. Furthermore, unsteady flutter calculations were conducted for cases both with and without flutter, allowing for a detailed analysis of the factors contributing to flutter occurrence. Through this investigation, the study established methodologies for aeroelastic design and evaluation, along with a proposed approach for preventing flutter generation. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study of lean flames stabilization with nanosecond repetitively pulsed discharges. The two-stage, swirled-stabilized, multipoint injector BIMER operates at atmospheric pressure with methane-air mixtures in the present study. It is representative in its design of a realistic lean premixed prevaporized injector of gas turbine engines operated at a lab-scale level. The lean blow-off extension with plasma is characterized. The combustion efficiency and the pollutant emissions are quantified near blow-off with and without plasma for 50-kW flames. We show that it is possible to stabilize lean flames down to an equivalence ratio of 0.3, with less than 5 ppm of NOX emitted, thanks to nanosecond repetitively pulsed (NRP) discharges with an electric power that represents less than 0.25% of the flame thermal power. This study also clearly shows that it is necessary to account for the plasma system integration at the early stage of the combustor design to fully benefit from the plasma stabilizing effects on the flame. [ABSTRACT FROM AUTHOR]

This paper outlines the update of a turbomachinery course to cover three-dimensional (3D) aerodynamics using a Reynolds-Averaged Navier Stokes solver. Prior to the activities outlined in this paper, the course was taught in a conventional way with a series of lectures and a timed, written, open book examination in a formal exam setting. Students were equipped with a calculator and set of notes including correlations from Howell and Soderberg. The students had around 1 h to answer the turbomachinery question, which was revealed to them only when they opened the paper at the start of the exam. This limited the depth of any aerodynamic problem they could get through and so they were restricted to simple design or analysis exercises. The genesis of the course update was the release in 2017 of "MULTALL OPEN" (Denton, J. D., 2017, "Multall: An Open Source, Computational Fluid Dynamics Based, Turbomachinery Design System," ASME J. Turbomach., 139(12), p. 121001), a freely available turbomachinery design system, and this was adopted as the course software--although other software choices were considered. Students now produce two turbomachinery designs during the course. These are both based on the J85 turbojet--largely to keep cycle calculations to a minimum but it was also important to ensure that students recognize that they were completing a real engineering task. The first task was a 3D aerodynamic design of multistage turbine, which includes compressible flow, tip clearance, and stacking techniques such as lean or sweep. The second task was a midspan (two-dimensional) compressor design. The exact cycle conditions were varied each year to explore design scenarios such as an increase in firing temperature. Assessment was by means of a short report where the best students report on their design choices, provide critical analysis of the design using appropriate postprocessing techniques, and compare their designs to the state of the art in the wider literature. As well as describing the successes and challenges of the update to 3D design methods the paper provides some guidance for educators thinking about adopting a similar approach. [ABSTRACT FROM AUTHOR]