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Computer Numerical Control (CNC) milling is still today the elective process for the production of single-piece impellers, as it can reliably produce complex geometries, removing the need for additional manufacturing processes. Nevertheless, Additive Manufacturing is winning more and more ground due to its ability to make components of any geometry that cannot be produced using subtractive techniques. As a result, the use of this technology can eventually be seen as the key to develop high-performance rotor components. In this scenario, the design of 3D impellers does not make an exception. Accordingly, the present paper proposes a general framework for engineered re-design and manufacture of 3D impellers installed on centrifugal compressors by exploiting Topology Optimization and Additive Manufacturing's potential. The procedure investigates also the rotoric component's best configuration for both static and dynamic behavior. Finally, the topology-optimized component is produced with AM through the use of suitable materials that can ensure efficient mechanical efficiency to prove the manufacturability of the entire procedure. To validate the proposed framework, the complete re-design of a 3D impeller of a major Italian-based Oil & Gas company is carried out, demonstrating that the re-thinking of the component in terms of Topology Optimization is a straightforward approach to increase the overall performance of the produced rotoric part.

Efficient maintenance of industrial equipment requires degradation monitoring and prediction. Currently used prediction models are mostly deterministic and cannot consider uncertainty inherent to degradation measurements. In this paper we propose using time series models obtained using Facebook Prophet algorithm to predict the evolution of degradation of turbomachinery. We illustrate our considerations with data from large scale industrial centrifugal compressors. Our predictions are promising and confidence intervals cover the predictions well.

New design approach to improve the turbomachinery performance is the research hot in various areas. In order to make up for the shortcomings about the uncertain design variables ranges and the simple 2D blade profile design method in previous studies, a modified inverse design approach established on the newly derived constrained zone and the PSO algorithm has been proposed in this study, and a developed design program with the Matlab platform was developed. With the adoption of the scaled 1:2.5 hydraulic model of the CAP1400 impeller as the target, the proposed joint design method was applied and verified.

The paper focus on the benefits of close integration of battery based energy storage directly into thermal plants. The attention is paid to use of the energy storage for primary frequency control in cooperation with classical steam turbine control. The model topology of the turbomachinery with all modifications is described and discussed. Three case studies are investigated – the primary frequency control managed by either only turbine, only energy storage and by cooperation of both turbine and energy storage. The other benefits of integration energy storage into power plant systems are discussed in the conclusion.

To improve the technical level of energy turbomachines in the present modern turbomachinery, high strength, reliability and durability are required in the design, manufacture and operation of turbomachines. The reliability and durability of a turbomachine is determined by the strength and resource of the most loaded structural elements of its rotor - impellers. Parts of the impellers (blades and disks) operate under conditions of enormous static loads from the action of centrifugal forces, pressure and uneven heating, and they also experience variable cyclic loads during forced oscillations from the action of gas forces. This paper presents numerical research of impeller vibrations with various types of mistuning and discusses the influence of mistuning parameters on the vibrational behavior of a bladed disk. A lot of research by different authors have shown that the phenomenon of mistuning parameters can have a significant effect on the resource of energy and transport turbine engines due to the fact that during forced vibrations of the impellers of turbomachines with mistuning parameters, the amplitude and dynamic stresses can increase dramatically.

This article presents mathematical finite element models for analyzing the sensitivity vibrations for compressor bladed disks of an energy turbomachines, which is performed a numerical analysis the vibrations and sensitivity of academic bladed structures with intentional mistuning. The research of mathematical modeling in the analysis of blade sensitivity can allow to significantly reduce the number of experimental research, which is needed to design the blade structures of energy turbomachines, as well as reduce the design time and increase the reliability of the blades and bladed disks. The sensitivity analysis of the blades gives the area of influence of changes in mass (as additional mass) on the natural frequencies and forms of vibrations of the blades, which is effectively used in the optimization of bladed disk structures. Using this analysis can obtain a decrease in stress levels and a change in the oscillation frequencies on the operating ranges of rotational speed turbomachine compressors.

Significant axial vibration of the turbomachinery rotor can cause destruction and failure of mechanical contact and dry gas seals. This paper provides an analytical technique to determine the possible separation boundary of the mechanical contact seal when its operation is affected by high amplitude and frequency of the axial rotor vibration. The proposed technique is confirmed by experimental data. The twomass dynamic model (stator and following rings masses) accurately describes dynamic processes in dry gas seals. However, significant axial rotor vibration can lead to the rotor sealing ring separation from the sleeve face on the rotor. This leads to the implementation of a three-mass model and a complex dynamic process, including the collisions between the rotor ring and sleeve faces on the rotor which can cause seal destruction and its failure. This complex dynamic process can be described only by accounting for the nonlinearity of the gas film stiffness and damping. CFD models of the seal gap are used to determine the dynamic performance of the gas film. The developed combined numerical and analytical technique can be used to predict the separation phenomenon and find an effective way to eliminate it when designing the seal.

The design and prototyping of jet engines is an extremely costly and laborious task. An alternative to at this is the development of variants of existing engines for enhanced performance which requires detailed modeling of engine in mathematical environment for precise evaluation of performance parameters. This paper presents mathematical modelling and sensitivity analysis of performance of RD-93, a low bypass turbofan engine, towards design parameters including pressure ratio of turbomachinery components, bypass ratio and critical temperatures. The effect of varying the efficiency of engine components on performance of overall engine is estimated using numerical environment of Numerical Propulsion System Simulation (NPSS). The results of performed analysis can serve as a guide for further parametric cycle analyses of low bypass turbofan engines.

The main goal of this work is in the qualification of temperature changes due to design modifications of the medium-sized turbo generator with the output power 40 MW, ie the temperature distribution of the active parts. The work summarizes of designing a number of changes in the cooling system of a 40 MW synchronous machine. The work is based on ventilation and thermal calculations to verify the change in flow rates, respectively, the flow rate of cooling air in the machine. Individual changes are first analyzed separately and then compared with the original state. Temperature trends and their comparison with the original solution are used to evaluate the impacts of design changes.

The main objective of the current paper is to establish an optimal configuration for a micro gas turbine, component of a combined heat and power (CHP) system. The design and modeling of the turbine rotor were achieved using CAE/CAD software. This paper will focus mainly on identifying issues regarding the mechanical resistance of the radial turbine. In order to increase the safety factor, a brief analysis of the designing mechanical stages was necessary. The CAD model for the optimal impeller was realized considering the facilitation of its manufacturing process and maintenance. The analysis is based on finite element method, implemented in NASTRAN. The characteristics of the material used are the following: density 8180 kg/m3, 1.67E11 N/m2 and υ = 0.28, for an angular velocity of 40 000 rpm. The presented paper aims to determine a functional configuration for gas turbine’s impellers, in order to effectively manage to deal with the conditions of temperature and mechanical stresses resulted in the exploitation of a CHP gas turbine. This objective was achieved after iteratively designing multiple configurations.

This paper presents the thermodynamic optimization of a 350 kW integrated combined heat and power gas turbine engine. The development of micro gas turbine engine depends on the thermodynamic cycle, thus this study is relying on the Brayton cycle with regeneration, taking into accounts the significant importance of the heat transfer efficiency within the regenerator and its impact on other parameters. The calculation methodology was implemented on an in-house code written in the Fortran 90 programming language. Multiple calculations were made, varying pressure ratios between 2 and 6 and regenerative effectiveness in the range of 47-80%. Following the analysis, a pressure ratio of 5: 1 was chosen with a mass flow rate of 2.6 kg/s. For technological reasons, the turbine inlet temperature was limited to 900 °C.

As an indispensable part of modern supporting technology, advanced hydrodynamic bearing still plays an irreplaceable role in turbomachinery. The high-speed turbomachinery in the 21st century still needs stable, low-friction bearings to support their rotors to run both smoothly and efficiently. Although various types of thrust bearings have been investigated in the recent year, they suffer from load capacity and instability problems. Nonetheless, the hydrodynamic bearing current design methodology still dependents on empirical design, lacking corresponding theoretical guidance. There needs to establish a universal rule about topology structure for a variety of non-circular bearings. The purpose of this paper is to focus on the static characteristics of hydrodynamic thrust bearings with topology design theory of Fourier series expansion of film thickness. Firstly, a universal mathematical expression for thrust bearings has been put forward based on the Fourier series theory. Secondly, the influence of periodic harmonics of film thickness on the static performance of different types of thrust bearings has been studied for the incompressible lubricant. Finally, the relationship between the k-th order harmonic component of the film thickness H 0,k and the static pressure component P 0,k of thrust bearing was established for various geometry parameters including the stepped, tapered and tapered-flat type. This method can be used to rapidly estimate the bearing capacity of the component, designed more excellent lubricating film carrier curve to significantly improve its carrying capacity. This new investigation method can be used to improve the performance of the new type of hydrodynamic thrust bearings.

Electricity storage is widely regarded as critical to a sustainable energy future, and currently deployed technologies such as pumped hydroelectric storage have drawbacks which limit the scale to which they can be implemented. Pumped thermal energy storage (PTES) has recently started to attract interest as an alternative. This article focuses on transcritical cycles and aims to identify the best working fluids, in a configuration with a single hot store and no cold store. Three different storage media were considered for the hot store: water, Therminol D12, and Therminol 66. For the transcritical cycle, 176 different working fluids were screened for thermodynamic, environmental and safety suitability, and the resulting list of 8 fluids was tested with cycles at a range of storage temperatures. The optimal round-trip efficiency is a trade-off between heat exchanger losses and turbomachinery losses. Pareto fronts were used to rank the fluids for efficiency, power density, and heat to work ratio. The most promising fluid was found to be trifluoroiodomethane (R13I1) with a peak round-trip efficiency of 57.6%.

This paper is concerned with the problem of constraint management for rotating machinery with actuators and sensors fixed in inertial space. Such systems arise in xerography, drilling and milling machines, and turbo machinery. The proposed approach consists of first discretizing the rotating device spatially and temporally to obtain a discrete-time lumped linear periodic model of the rotating device. Linear tracking controllers are then designed to stabilize the system, followed by the application of the Reference Governor (RG) technique for constraint management. To accomplish the latter, we extend the earlier results in the literature of RG to the case of periodic systems with disturbances, which arises in applications. We illustrate the theory using a numerical simulation of the fusing stage of a xerographic process.

Torque converters are key components in automatic transmissions used in vehicles, construction machinery, etc. The development of hydraulic torque converter is toward high capacity, high speed and high power-weight ratio, which requires higher mass flow rate, leading to higher risk for cavitation. Cavitation is a transient phenomenon which involves phase exchange between liquid and vapor, and heavy cavitation in torque converter brings about severe performance degradation, noise, vibration and even failure depending on the degrees of cavitation. However, as torque converter is a closed-loop multi-component turbomachinery, it’s hard to have access to the internal cavitating flows. Thus, the transient cavitating flow behavior remains unclear. Therefore, this study investigated the dynamic cavitating flows inside a torque converter using transient multiphase computational fluid dynamics (CFD) model. The effects of cavitation on the hydraulic performance and the evolution mechanism of cavitation in the torque converter were investigated, and the numerical model is validated against test data. The proposed transient CFD model was able to predict the cavitation characteristics with reasonable accuracy. The results indicated that cavitation mainly occurred in the stator domain, and it brought about over 20% degradation in torque capacity.

The expanding of application in renewable energy based on small power plants for remote area is more attractive due to global warming and climate change concern. The power plants can be improved by increasing wide-range operation, variation working fluids, and operating point in turbomachinery components, such as the radial compressor. In the early stage of the design system, it is not easy to find and determine the radial compressor performance map in the open literature. In this paper presents an empirical model and simulations for predicting performance map of the radial compressor. The models were carried out Casey-Robinson method combine with Ludtke method. Furthermore, the models were implemented in Python and GT-Suite. The result shows a satisfying trend predicting curve performance map for the radial compressor. This adopted model can be support for acceleration in the early stage of the design of power plant base-on renewable energy such as Solar Hybrid micro-Gas Turbine (SHGT) system and Parabolic Dish Solar Collector (PDSC) system.

The object of research is dynamic behavior of the high-loaded details of power turbomachines rotors, which fatigue life defines fatigue life of the entire turbomachine. In this article a frequency spectrum and sensitivity function of rotor model blades with blade shroud at their free and fixed condition (contact) are analyzed. The numerical analysis of strength characteristics and free vibrations frequencies sensitivity of rotor blades to construction thickness (weight) variations is executed by means of the software package BLADIS+. The calculation results are confirmed by the experimental data. The offered and approved algorithms, mathematical models and numerical techniques are to be used for new and existing power turbomachines rotors structural designing. Mathematical modeling of such cases allow minimizing research charges, designing time and increasing a power turbomachines lifetime.

Rotor-bearing system is the core structure of turbomachinery, transmission trains and other rotating machinery. Its dynamic characteristics directly influence the performances and the safety operation of the whole system. In most situations of practical engineering, the rotor-bearing system is required to work under a low vibration mode for high rotation accuracy. It is an extreme case that rolling element bearings are facilitated for the support of high speed turbine rotors. Squeeze film damper has its capability of damping the vibration energy transmitted between the rotor shaft and the bearing pedestal. Its integral version, the integral squeeze film damper (ISFD), has the advantages of small volume, low mass and simple structure, which are well suited for the stable running of high-speed rotor-bearing structure. Considering the elastic support of both ends of the rotor shaft, misalignment generally exists between the rotor axis and the central connection of two support bearings. Thus, in this paper, the dynamic characteristics of a rotor-bearing system with ISFD are studied based on the established 9-DOFs model. Misalignment and the unbalanced mass are considered in the model to evaluate the system performances under such excitations. It is concluded that the ISFD supported system is more stable than the ball bearing supported structure. Besides, the ISFD is capable of suppressing the vibration energy induced by coupling misalignment with some pre-designed damper parameters.

Application of hybrid bearings, which combine rolling-element and sliding bearings allows significant improvement of dynamic characteristics and increase of lifetime of turbomachinery. In the present paper a general approach is presented for mathematical modeling of a hybrid bearing and of a control algorithm of its dynamic characteristics for rotor vibration minimization.

This paper deals with ventilation - thermal calculation of the medium sized turbo generator with the output power 40 MW. The temperature and airflow were calculated using “Ansys Fluent”, The described work follows up on the ventilation calculation done in past. In particular, there are several options tested to figure out the behavior of the numerical model. The ventilation part of the numerical model was tuned according to analytical calculations, so it should be trustworthy. The individual options are characterized as reduction or addition of the flow cross section (flow inlet to transfer ducts, air gap inlet). The results show advantages and disadvantages of those options, also show the way how to improve the cooling compartment system of a turbo generator.

We discuss a novel measurement system based on passive Variable Reluctance Magnetic Sensors (VRSs) to provide clearance measurement for turbo-machine monitoring. The advantage of the solution is in its reliability and low-complexity (in terms of sensor structure, costs and electronic front-end), against an acceptable measurement accuracy, making the proposed method suitable for the condition monitoring of huge turbo-machines requiring a large number of sensors.

Nowdays, the use of alternative sources of energy has gained much importance due to the reduction of fossil fuel reserves. The supercritical CO 2 power cycle is being used in applications for power generation with different sources of heat including solar. The main components for a Brayton power cycle are those for turbomachinery group. The purpose of this paper is to present the one-dimensional design development of a turbine for a supercritical power cycle using CO 2 as working fluid. The procedures here presented take into account the design process of a radial turbine due to the small size found in this component for a supercritical fluid.

Fluid machinery courses demand, besides theoretical approach, also good practice and laboratory exercises. After course completion, students should be aware of all aspects of good practice and possible problems. Focus of this paper is on hydraulic pumps and designed demonstrational-educational test rig. It is possible to demonstrate and educate students in following: Bernoulli equation, Euler equation for turbomachinery, hydraulic losses, Venturi flow meter — geometry and measurements, cavitation and swirling flow phenomena, as well as in practical issues such as pump testing after international standard ISO 9906, pump control and energy efficiency issues, determination of hydraulic system characteristics, volumetric calibration of the Venturi flow meter, and etc. Students are educated how to choose and connect pressure transmitters, as well as how to calibrate them, how to apply and upgrade developed LabVIEW application. In addition, many components of the installation are transparent, such as pipes at the pipe inlet and pressure side, Venturi flow meter, main and calibration tank, as well as pump spiral casing. Flow visualization and application of modern measurement technique, such as particle image velocimetry are possible in this way. Following experiments of this test rig, students are motivated to generate technical electronic report. In addition are presented virtual experiments, designed in LabVIEW for testing pumps in parallel and series modes.

The turbine-governor models that are currently used in studies of power systems include over-simplifications of turbomachinery elements. Due to the growing need to support intermittent energy resources with other energy sources like gas turbines, more detailed models including an explicit representation of the physical dynamics are attractive. In this paper, the advantages of the Modelica language and the FMI standard are considered to carry out modeling and multi-domain simulation of gas turbines with power grids, which can be used to evaluate scenarios of power variability. The work gathers preliminary results of the potential that FMUs offer to promote the exchange of turbine models by manufacturers and to conduct multi-domain simulations in several tools.

Multi-frequency phase-lagged boundary condition has the advantage of reducing the computational domain to one single blade passage per row in unsteady flow simulation of a multistage turbomachinery, which saves the requirement of computer memory and time. The first part of the paper presents the implementation process of this approach in CFD code to predict unsteady flow field in multi-stage turbo-machinery. Unsteady simulations and steady simulations are then performed on a 3.5 stage compressor. Compared with the steady results, the compressor performance predicted by unsteady calculation match much better with the experimental data. The flow field of neighboring blade passages per row in compressor appears different due to the unsteady interaction of rotor and stator. The blade surface pressure distribution of middle stators fluctuate in large amplitude especially at the trailing edge of the stator. The interaction between stator blades and forward shock wave of the downstream rotor under small axial gap is the key factor of stator blade pressure fluctuation.

The paper contains a comparative estimation of the efficiency and energy consumption of an induction motor (IM) and a synchronous reluctance motor (SynRM) in an electric drive of a variable-speed pump unit with a capacity of 0.75 kW. The paper considers an IM of the IE2 class and a SynRM of the IE5 class. In order to determine the motor efficiency, a polynomial interpolation procedure based on 7 standard load points is used. The losses for determining the efficiency of the IM are calculated on the basis of the data given in the EN 50598-2:2014 standard. The losses for determining the efficiency of the SynRM are used on the basis of the data on losses given in the catalog provided by the manufacturer. The justification for the approach used to compare the energy properties of the motors, which includes calculation of the energy consumption of the pump unit depending on the process load, is given. With the calculation of the energy consumption, it is shown that the use of the SynRM, in comparison with the IM, makes it possible to significantly reduce the power consumption of the pump unit.

Understanding of the aerodynamic unsteady flow interactions is essential for improved performance of the modern turbomachines. The performance of a highly loaded transonic turbine is strongly influenced by the unsteady impact of stator trailing edge shock wave on the rotor. In this paper Three-Dimensional unsteady Navier-Stokes calculations of a single high pressure transonic turbine stage are presented. The numerical results predict the flow physics and the unsteady loss generation mechanisms fairly well in the transonic turbine stage. The flow domain is completely described by the velocity flow field and turbulent kinetic energy distribution at various planes behind the stator and rotor. Furthermore, the static pressure distribution at midspan helps to explain the stator-rotor interaction mechanism. The stator trailing edge shock wave impinges on the suction side of the passing rotor blades and reflected back intermittently thus setting up a periodic wake shedding phenomena. The reflected shocks interact with the boundary layer on the suction side of the stator near trailing edge and also on the rotor blade surface while transported through the rotor passage. The stator wakes are chopped by the passing rotor blades and convected through the rotor passage and thus influencing the rotor trailing edge flow. The unsteady pressure fluctuations showed that rotor suction side bears more fluctuations due to the accumulation of stator wakes on it. The understanding of unsteady flow physics and the loss generation mechanisms in turbomachinery will aid to develop methods to design highly efficient machines.

This paper presents the numerical optimization of axial-flow hydraulic turbine performance. The turbine was designed to operate at a net head of 0.9 meters, a rotational speed of 500 rpm, and maximum flow rates are 0.12 m3/s. The initial turbine design was optimized by using shock-free inflow criterion to minimize the hydrofoil losses at the turbine cascades. Potential flow of the hydrofoil was analyzed using surface vorticity model with modified coupling coefficient to deal with turbomachinery blade cascades. The ABC algorithm was used to arrange the geometry of guide vane's and runner blade's cascades to meet the shock-free inflow criterion. In the present study, the cascade geometry optimization of the axial-flow hydraulic turbine is divided into two main steps. Firstly, cascade at each section of guide vane was optimized by arranging two design variables, i.e. stagger angle and chamber line of the hydrodynamic profile. Secondly, cascade at each section of runner blade was optimized by arranging one design variable, i.e., stagger angle. Both steps have the same objective function that minimizes the difference between the design of inlet flow angles and shock-free inflow angles. The optimization results showed that the ABC algorithm performed very well, the average of best values at each section was an order of magnitude of −14. The performance of turbines was predicted using computational fluid dynamics (CFD) approach based on finite volume method. The numerical results showed that the optimization of two-dimensional cascades geometries by using shock-free inflow criterion successfully improved the performance of initial design of axial-flow hydraulic turbine.

High-speed rotated blades are key mechanical components in turbomachinery. Understanding dynamic characteristics of rotated blades is important for damage detections in turbomachinery. Conventionally contact methods are used for this purpose. However, strain gauges and accelerometers can affect the precision of measurements. So blade tip-timing(BTT) is used to realize non-contact vibration measure and then using accurate measure results to detect damage in rotating blades. However, BTT signals are typically under-sampled. How to extract characteristic features of blade vibrations by under-sampled signals becomes a big challenge. In this paper, a novel of compressed sensing (CS) is proposed to solve the problem. Firstly, a CS mathematical model is built based on BTT method. Then, minimum one normal(L1) algorithm is applied to solve the CS problem. Finally, damage detections are realized based on reconstructed frequency information. Thus the proposed method can provide a promising way for online damage detection in rotated blades for practical engineering.

This article describes the results of optimization of the working process parameters (overall pressure ratio and turbine inlet temperature) of small-scale turbojet for cruise missiles and target airplanes. The influence of engine scale factor upon the efficiency of turbomachines, as well as the principal operational constraints were taken into account during the multi-criteria optimization. Specific fuel consumption and the total mass of engine and required fuel were selected as the optimization criteria. Optimal regions of the working process parameters were identified for the turbojet engines of thrust ranging from 0.1 kN to 2 kN. The results show that different types of turbomachinery (e.g. axial vs. centrifugal compressor) have substantially different optimal regions, thus the stage of optimization of working process parameters for the small-scale engines could not be implemented independently, unlike the full-sized engines. According to results, the optimal values of working process parameters decrease as the engine scale factor decreases, and the optimal regions shrink too. The results presented in this paper also include the most efficient values of the working process parameters and the rational types of turbomachines for various thrust levels and aircraft missions.

The article describes the thermogasdynamic model of small-scale gas turbine engine. This model takes the engine size into account during the efficiency assessment. The engine size is defined by the value of mass flow rate corrected by parameters at the exit of the compressor. The important features of working process of small-scale gas turbine engines are the increased hydraulic losses and decreased turbomachinery efficiency due to the increasing of a boundary layer relative thickness and relative tip clearances. This article describes the mathematical models that provide the corrected values of turbomachinery and combustion chamber efficiency ratios. This approach provides more adequate results of working process parameters optimization and may be used for conceptual designing of micro gas turbine engines.

8th International Conference on Mechanical and Aerospace Engineering (ICMAE) -- JUL 22-25, 2017 -- Prague, CZECH REPUBLIC, WOS: 000427156200055, This paper analyzes and evaluates exergetic improvement rate (IPex) of the components of a small turbojet engine with various turbine inlet temperatures. The engine consists of an inlet, starter generator, a centrifugal compressor, a reverse flow combustion chamber, an axial-flow turbine and an exhaust nozzle. IPex analysis is performed on this turbomachinery utilizing kerosene as a fuel. Exergetic analysis is applied to the turbojet to investigate the turbine inlet temperature effects (i.e., turbine material improvement) on the IPex of each component in the engine using different turbine inlet temperatures at a constant reference environment., IEEE

In this paper, a control-oriented model for compressor mass flow rate is proposed. For this purpose, the compressor is approximated as an adiabatic nozzle with compressible fluid, driven by external work from the compressor wheel. The external work input is modeled using Euler's turbomachinery equations, with the main flow losses estimated via a simple slip factor model. All other flow losses, that influence the mass flow, are lumped into the discharge coefficient as a function of turbocharger speed. Consequently, the mass flow rate is estimated based on mass conservation in a compact form. Only five parameters need to be identified with clear physical interpretations. Both steady-state and transient experimental test results confirm the validity of this model in terms of estimation accuracy and extrapolation capability, making it a promising candidate for control applications.

High speed generation derives its motivation from a variety of applications such as concentrated solar power (CSP) generation, hybrid automotive power generation and aerospace. Research is actively been pursued in the field of power generation using solar heat, where novel thermodynamic cycles like supercritical carbon dioxide (sCO2) Brayton and Organic Rankine Cycles are considered as superior options over conventional steam and gas turbine based cycles. The inherent feature of these cycles is high speed turbomachinery which demands a compatible high speed generator for an efficient turbo-generator power block. Switched reluctance (SR) machines are inherently advantageous for high-speed operation since the rotor is magnet free, carries no current, and can be constructed using a single material. This paper investigates the structural and rotodynamic aspects of a 5 kW, 10000 rpm, 6/4 pole switched reluctance generator. The rotor is devoid of laminations and is a single solid body. Preliminary results show that the effect of centrifugal loading on radial deflections is higher than the radial electromagnetic forces. The critical speeds are widely spaced from the desired operating speed.

The paper discusses results of integration of experimental campaign with CFD studies, where a small wind turbine placed inside a wind tunnel test section has been examined. Investigation included determination of model size influence on flow blockage effects. The CFD model helps to reduce time spent at the experimental stand and, therefore, costs pointing to the model with acceptable dimensions. CFD has been also used to anticipate the loads that may be exerted on the model thus helping to understand necessary measures in the upcoming aeromechanics study of the construction. The study concerns a wind turbine placed inside a diffuser channel, a solution known as Diffuser Augmented Wind Turbine (DAWT). This type of wind energy converter has recently been an object of numerous studies at the Institute of Turbomachinery of Lodz University of Technology. The examined model sizes included: D_5, D_10, D_20, D_30, D_80 and D_real, where the number states the per cent of test object's cross section area related to the cross-section area of the wind tunnel outlet nozzle supplying air to the test location. The numerical study has been based on a commercial solver ANSYS CFX 15.0, the comparison of the obtained results with available experimental data for D_5, D_30 and D_80 models has been made, leading to the analysis of the results obtained and the conclusions.

The paper discusses results of examination of various wind turbine rotor models implemented in numerical simulations, with particular emphasis on the interaction of a rotor with the surrounding airflow. The study concerns a wind turbine placed at the inlet of a divergent duct, a solution known as Diffuser-Augmented Wind Turbine. This type of wind energy converter has recently been an object of numerous studies at the Institute of Turbomachinery of Lodz University of Technology. The study focuses on the search of wind turbine evaluation method combining high accuracy and tolerable time-to-results factor. The examined models include: FRM (Fully-resolved Rotor Model), ADM (Actuator Disk Model) and authors' modified approach to ALM (Actuator Line Model). The study covers: the implementation of the above mentioned method(s) into a commercial solver ANSYS CFX 15.0, the comparison of the obtained results with available experimental data, the analysis of the results obtained from simulations and the discussion. The paper is characterised by the wide spectrum of actuator models compared with 3D accurate rotor modelling for the estimation of turbine performance, the authors' proposal of the ALM variant, and the comparison of the models also from the viewpoint of the numerical effort (computation time and resources necessary) they require.

The paper addresses the design of Distributed Control Architectures (DCAs) for the control of complex turbomachinery systems such as gas and steam turbines for Oil&Gas and Avionics. While the use of DCAs is a strong reality in the automotive industry, in the Oil&Gas application fields DCAs are not yet widely used and a centralized control system is often adopted. This work presents a high-level modelling activity of the control system for Oil & Gas turbomachinery including a tool for the design space exploration, evaluation algorithms, cost metrics and performance indexes. The aim is the optimal system partitioning in the transition from a centralized to a distributed control architecture. As example case study the proposed approach is applied to the control system for a gas turbine produced and distributed by GE Oil & Gas — Nuovo Pignone.