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The choice of the type and configuration of the engine, as well as ensuring its coordinated operation in critical modes to minimize thrust losses, have a significant impact on the fuel-economic and environmental performance of a high-speed passenger aircraft. Research work in this area is aimed at developing and improving the methodology for forming layouts and assessing the aerodynamic, flight performance, and economic characteristics of supersonic passenger aircraft with an acceptable level of fuel efficiency, high flight safety, and low levels of sonic boom and noise. In the field of aircraft engine building, using modeling methods, it is necessary to provide a lead vector for the formation of a scientific and technical reserve for creating competitive engines in the shortest possible time. This paper presents the results of optimization of HPC blade angles and a variant of the engine with a constant high-pressure turbine is formed. [ABSTRACT FROM AUTHOR]

Rudder is one of a primary flight control surface of an aircraft and have the function as directional control and directional trim. For multi-engine aircraft, critical function of the rudder is to be able to maintain aircraft direction in case of one engine inoperative. Due to aerodynamic load, the higher rudder deflection the higher hinge moment acting on the rudder. For the aircraft equipped with mechanical control system, load on the rudder can be feel by the pilot on the pedals. Excessive load received by the pilot in long duration of operation can make tired the pilot. Maximum load on the rudder allowed by regulation in VMCG with OEI is limited to 150 lbf. Current design of the rudder still produce load higher than limit value, even aerodynamic balance e.g., servo tab and rudder horn has been implemented. Sensitivity study of rudder horn balance was carried out to improve rudder hinge moment to reduce pedal force. This study was conducted by means wind tunnel testing in the NLST in Bandung, West Java. 6 rudder horn balance model was tested, the result are compared including basic or current horn design. Horn 8 provide the best result compared to basic horn and other modified horn, it is meet requirements both for load limit of 150 lbf and safety aspect. [ABSTRACT FROM AUTHOR]

This paper describes the process of simulating the performance of the Rotax 915 iS engine used on the PUNA MALE. The performance simulation is performed at ground level employing wide open throttle, typical Indonesian operation temperature 30 deegre Celsius. The aim of this paper is to conduct simulation of performance of the Rotax 915 iS engine to confirm the performance data issued by the manufacturer, and also to predict engine operation on the aircraft. This simulation is performed using AVL boost software, which employs a zero-dimensional and one-dimensional modeling system. The application of this software necessitates the creation of a virtual engine model, then requiring to enter engine component parameter data. Engine data parameters can be taken from the engine manual, whereas data not available from the manual can be obtained by carrying out measurements or searching from other sources. The performance results that can be obtained include: power, torque, fuel consumption and brake specific fuel consumption (bsfc). Simulation results show relatively small difference with the engine data provided by the engine manufacturer. Comparison of the simulation results of performance to engine data from manufacturer show an agreement in the trend of values for increasing engine speeds. However, there exists larger difference values at high engine speeds. [ABSTRACT FROM AUTHOR]

The paper discusses the derivation of criteria for pollutant mineral matter in fuel that is hazardous for fuel metering equipment (FME) of aircraft jet engines. It is concerned with mechanical impurities captured during fuel transportation, pumping, draining and storage, and with quartz of various range of dimensions. With optical microscopy and the requirements for model matter to obtain a mathematical description of the aviation fuel sedimentation process based on a particular solution of the Navier-Stokes equation, a sphericity coefficient of 0.835 was adopted for a ball. Based on the data obtained, 4 criteria for matter hazardous for FME were identified: hardness, size, density, shape. [ABSTRACT FROM AUTHOR]

The key objective of this work is to achieve finite element method (FEM) analysis to find an optimal design of a concentric spring used for an aircraft engine valves through investigating several composite materials and predict the compatible design one. For that, it has been attempted to identify the most suitable composite substance which might the alternates in place of traditional material of an aircraft engine valves concentric spring, for that four case studies of various material have been inspected for the similar design pattern dimensions and loads. These case studies of the concentric spring of aircraft engine valves are contacted steel alloy as traditional material, Epoxy carbon, Epoxy Glass and hybrid concentric spring material in which one of the spring made from a steel and the other from carbon fiber. The FEM inspection has been organized all the above substances to find out the exceptional case study as an alternate case of the aircraft engine valves concentric spring. The outcomes have been pointed out that the case study of the hybrid material of the concentric spring can achieve a better static and dynamic results among the others spring material and can be utilized as an alternate material for the composite spring of that can be designed with the engine valves. [ABSTRACT FROM AUTHOR]

In this paper, dodecagonal fuzzy number plays an important role in analysing the failure rate of aircraft engine. The conditions for the failure of the engine is taken into consideration and with the help of dodecagonal fuzzy number, the reasons have been studied and a solution for it has been given. The mathematical approach seems to have a high impact in analysing the failure rate of an aircraft engine. It helps us to investigate the reason at the fastest time possible which reduces time complexity. [ABSTRACT FROM AUTHOR]

Impact of aircraft on the atmosphere studied specifically their effect as a source of air and water pollution and how they contribute to the transmission or spread of diseases such as Covid 19. Aircraft engines generate various gases like carbon dioxide (CO2), including around 70% of the exhaust, and water vapor (H2O), which provides about 30%. Lower than 1% of this exhaust is consists of pollutants such as oxides of nitrogen (NOx), sulfur oxides (SOx), monoxide of carbon (CO), and especially combusted or unburned hydrocarbons (HC), particulate matter (PM), and other components. In addition, many pollutants formed in combustion convert when they are emitted into the atmosphere. All these emissions are a significant source that contributes to environmental pollution. Also, in our current days, we notice the spread of Coronavirus significantly with the increasing cases of travel and movement between governorates and countries, which makes transportation in general one of the causes of its spread as this virus travels through the air and thus affects human health in a very negative way. Statistical analysis of the impact of aircraft on air and water pollution and the problems of COVID 19 have been investigated. With the rapid development of equipment and technologies used in airplanes, and therefore current-days, airport transmission has been widespread attention with a focus on social and economic well-being, environmental activity, and protection towards sustainability. [ABSTRACT FROM AUTHOR]

Aircraft engine run-up is one of the maintenance activities that produce noise. Since most of the maintenance activity performs in the evening or night and takes a longer time than take-off or landing, noise could be more disturbing for residence around the airport than normal aircraft operations. Engine run-up facility is not always available for every airport. This research estimate noise level based on noise data from aircraft manual and distance between source and receiver around the airport. The noise level is also influenced by the directivity of the noise source. Since the duration of engine run-up is considered, Sound Exposure Level (LAE) is used as a noise level parameter for comparison rather than maximum A-weighted noise level (LAMAX). Calculation using B737-800 noise contour data with receiver position at 1000 m distance and 30° direction has LAMAX 64.5 dBA and SEL 82,3 dBA for 60 seconds run-up duration. Direction change to 135° has result 78 dBA and SEL 95.8 dBA. SEL will increase 7 dBA if run-up takes 5 minutes. The simple calculation method in this research could be used by airport personnel or maintenance personnel for determining engine run-up location, duration, time, and aircraft heading based on the distance and position of the residence around the airport. [ABSTRACT FROM AUTHOR]

The issues of the introduction of the converted GTE NK-361 on liquefied natural gas (LNG) into train traction are considered. The advantages of a gas turbine engine when operating on railway transport in general and in the conditions of the North in particular are shown. A project of a hybrid gas turbine locomotive with a booster section of power storage units GT1h "Pavlovich" is presented. [ABSTRACT FROM AUTHOR]

This work show the analysys of a three different airfoil geometris, that shows the turbine design and how important are this for the existent technologies. The imporante of cavitation and other physics phenomes it's a critical point on blade design, this mean that its necessary create many profiles and operation conditions, like free surface separation, blade high, cavitation and the influence of the diffusors applied directly to the turbine design and the effects that all this phenomens has into the blade design. [ABSTRACT FROM AUTHOR]

The article implements information and analytical fixation of ground-level gas contamination from functioning aircraft engines for a number of polluting ingredients at a specific facility. It is established that at the aviation profile facility, the integrated background of the accumulation of polluting ingredients is maximally generated in the working area of the energy and test technogenic service area in quantitative terms and in the diversity of the components released. The qualitative composition of gas mixtures emanating from mobile diesel generators when starting aircraft engines was recorded: CO, NOx (total NO2 and NO), C, CH (total hydrocarbons), SO2, CH2O, C20H12 (3,4-Benzpyrene). An analytical assessment of the maximum single and gross emissions of partial i-th pollutants in the exhausts of stationary diesel generators has been carried out. The information of analytical calculations showed the presence of CO and NOx dominance in diesel generator exhausts (NO2 and NO in total). Emissions of polluting ingredients were quantitatively identified from bench measuring systems of racing tests of aircraft engines. For 2 types of aircraft engines DVS-1 and DVS-2, mainly launched for bench runs, an analytical calculation of the functional attributes of contamination has been implemented: cumulation of the i-th pollutants during the take-off and landing cycle interval departing from the aircraft and gross emissions. For the internal combustion DVS -2, taking into account the limiting factor - the maximum concentration of emissions, an analytical calculation of the maximum one-time accumulation of polluting ingredients emanating from genesis into the atmosphere was carried out. It was recorded, during the control diagnostics of the operability and reliability of aircraft power plants on bench measuring systems, according to analytical calculations, for the second test site of the facility, the dominance of CO, NOx (NO2 and NO in total) in the exhaust emissions from engines [ABSTRACT FROM AUTHOR]

This paper presents the results of the research on the possibility of providing requirements for the noise of civil supersonic aircraft using its propulsion system controlling. The methods are based on the use of an engine mathematical model embedded in digital automatic control system. The use of EMM provides real-time calculation of the engine operation parameters that are not available for the measurement, including those affecting the amount of noise. An important part of the engine mathematical model application is the model identification during the operation of the engine. Focusing on a turbofan engine it is shown that during takeoff and landing the use of such control can significantly reduce the jet velocity, which helps reduce the noise level. At the same time, the thrust is maintained at the required level. [ABSTRACT FROM AUTHOR]

Reliability is one of the most important factors to consider when choosing a vehicle, and while the aircraft is one of the safest means of transportation, work is underway to improve the reliability of the aircraft. The aircraft is constantly equipped with systems that detect danger even before it occurs, such as a fire alarm system or an anti-icing system. This study will present a modern system for protecting the engine turbine from damage and thus improving reliability of the turbines, which leads to an increase in the reliability of the engine and the aircraft as a whole. [ABSTRACT FROM AUTHOR]

Gas turbines play a serious role in aviation due to their high power-to-weight ratios and compactness in comparison to other conventional power generating units. The principal characteristic of the turbine blade is imparting power to or extracting it from numerous fluid streams. Turbine blades are exposed to a mix of high operating temperatures, centrifugal and bending loads due to shock loads as well as erosive/corrosive effects during operation. These operating conditions make the blades most vulnerable to failure and demand periodic inspection which adversely affects the general operational costs. In this paper, we present a study of problems related to gas turbine blades and by taking fatigue into consideration, we present a framework that successfully uses a combination of Reverse Engineering (RE) and finite element analysis (FEA) to model, analyses and optimizes different material properties which has an optimal performance of gas turbine blades for aircraft engines. Thermal fatigue and stress analysis are carried out and fatigue life cycles of different alloys are calculated [ABSTRACT FROM AUTHOR]

An experimental and theoretical study of fracture mechanisms of the AMg6 alloy at different structural levels was carried out under consecutive shock-wave and fatigue tests associated with conventional catastrophic events of aircraft engine components (fan blades) due to the foreign object damage and the life-time decrease in the presence of a corrosive environment. The test program for shock-wave loading of massive flat targets made of aluminum alloy AlMg6 with profiled impactors (explosive generator method) initiating controlled damage of various levels in the volume of the material was implemented experimentally, followed by the application of an ultra-high cycle load (the number of cycles 107–109) on samples specially prepared from the target material samples. Fatigue tests of preloaded samples were conducted on Shimadzu USF-2000 ultrasonic fatigue testing machine with the cooling by abundant compressed-air and salt fog (3% NaCl). [ABSTRACT FROM AUTHOR]

Recently, a new trend has been observed: the world's leading aircraft manufacturers are actively introducing 3D printing technologies (rapid prototyping and additive manufacturing of finished products) into design and manufacturing processes. In order to maintain its position in the world market, an enterprise must constantly seek competitive advantages, expand its product range and avoid technological lag. The article discusses the main options for using additive technologies in the production and repair of aircraft and aircraft engines. The article deals with the main issues of the application of advanced information technologies and risk management systems at aircraft manufacturing enterprises. Topical directions of increasing the efficiency of risk management of aircraft manufacturing enterprises through automation are considered and the main problems of the development and use of such technologies and systems are analyzed. [ABSTRACT FROM AUTHOR]

Recently, a new trend has been observed: the world's leading aircraft manufacturers are actively introducing 3D printing technologies (rapid prototyping and additive manufacturing of finished products) into design and manufacturing processes. In order to maintain its position in the world market, an enterprise must constantly seek competitive advantages, expand its product range and avoid technological lag. The article discusses the main options for using additive technologies in the production and repair of aircraft and aircraft engines. [ABSTRACT FROM AUTHOR]

Turbine engine noise is one of the problems that contribute to an environmental issue in noise pollution. The problem also one of the major concerns for the aircraft engine manufacturer and various approach has been taken to counter the issue. The strict airport noise regulation and the stringent standard noise control from authority made this issue more crucial in the present and become significant in aeroacoustics research. This paper surveys various types of nozzle application for the reduction of noise emission. The input from the literature survey determines the best design that can be used for the turbofan engine or turbojet engine with minimal effect on engine performance. Then, the discussion focuses on the Chevron design process and performance to look at the opportunity to improve the current approach. The suggestion that can be made to improve the efficiency of the chevron is by adding the vortex generator on the core nozzle. The vortex generator should be inserted at the location before the smaller area of the exhaust core. By adding the vortex generator, it will help them produce the streamwise vorticity hence will assist in mixing enhancement between the core and the bypass flow. [ABSTRACT FROM AUTHOR]

A method was developed for prediction of the acoustic characteristics of resonant liner samples based on numerical simulation of physical processes in a normal incidence interferometer. Numerical simulation was performed based on direct solution of the non-stationary compressible Navier-Stokes equations in a three-dimensional formulation. The studies were carried out for full-scale multilayer samples of honeycomb acoustic liners with geometric characteristics close to those actually used in aircraft engines. The results of computations were compared with results of prediction based on semiempirical model and with results of natural experiments on normal incidence interferometer. It was revealed that the acoustic characteristics obtained by numerical simulation are in better agreement with the results of natural experiments than those determined by semiempirical model. [ABSTRACT FROM AUTHOR]

Erosion is the most prominent issue in several engineering applications such as hydropower plants, steam/jet turbines, aircraft engines and chemical processing equipment. Solid particle erosion limits the working span of the slurry handling components. Therefore, it is very crucial to determine critical factors for design, selection and operation of the hydraulic conveying system. Engineering interest is to estimate the working life of slurry handling equipment subjected to slurry erosion and to investigate the possibilities of enhancement of their service life. Therefore, in the present review, a brief description is provided in terms of various types of slurry erosion test rig used to stimulate the actual condition of slurry handling equipment by several researchers. On the other hand, the influence of tribological operating factors such as impact angle, solid particle velocity and erodent concentration on solid particle erosion wear is also described. Finally, it was summarized that most of the researchers were used slurry jet apparatus (47%) followed by slurry pot (35%), high energy slurry pot (11%) and coriolis apparatus (7%). It was also concluded that impingement angle and impact velocity is the most significant tribological parameters for the erosion wear. The conclusions drawn from this review will help a new researcher in the scope of slurry erosion wear. [ABSTRACT FROM AUTHOR]

In this work, several methods for combined reactor modeling of carcinogenic polycyclic aromatic hydrocarbon (PAH) concentrations in aircraft combustion chambers for kerosene combustion were proposed and investigated. Settlement and experimental studies were carried out for a model combustion chamber of a small engine using three different combined approaches based on the results of three-dimensional CFD modeling. The first approach is to create a chain of sequential perfectly stirred reactors (PSR) and to replace individual combustion zones with reactors. The second approach uses ANSYS Fluent's automatically generated chemical reactor network (CRN). The third approach implements automatic generation of reactor chains according to a user-defined algorithm in the kinetic post-processor of the Chemkin Energico or KPPSMOKE program. We studied the atmospheric pressure combustion regime for liquid kerosene, with an air temperature behind the compressor of 423 K and an equivalence ratio of φ=0.22–0.33. PAH concentrations were determined experimentally by high performance liquid chromatography. As a result of the work, it was demonstrated that only the approach using kinetic post-processors shows the orders of PAH concentrations corresponding to the experimental ones. [ABSTRACT FROM AUTHOR]

A Brayton engine is one of the heat engines that convert heat energy into mechanical work. This engine is often implemented on turbojet engines of airplanes and gas turbines. However, the efficiency of a classically Brayton engine still needs to be improved according to the second law of thermodynamics. This research presents a Brayton engine on 2D symmetric potential well. The used method is modeling analogy of the first law of thermodynamics and then it is implemented into a quantum system with the single-particle as a working substance. The primary result obtained is the efficiency formulation of a quantum Brayton engine for 2D symmetric potential well which is similar to the 1D quantum Brayton engine and the classical Brayton engine. Quantum Brayton engine in 2D has a higher efficiency compared to the 1D and the classical one. [ABSTRACT FROM AUTHOR]

Abstract. This study compares the shape of a plate blade with an aerofoil blade using computational fluid dynamics (CFD) to determine which blade shape is more suitable for use with open flume turbines (OFT) featuring the pico scale. The CFD method with six degrees of freedom (6-DoF) is used because it represents more precise flow patterns. Based on the simulation results, the boundary conditions of discharge are 40 L/s and 60 L/s; thus, plate blades have greater efficiency than aerofoil blades. This is because the pressure gradient at the leading edge of the plate blade is higher than that of the aerofoil blade. A high gradient pressure on the blade can augment the lift force, increasing the runner’s torque. Overall, the plate blade profile is suitable for OFT featuring the pico scale. [ABSTRACT FROM AUTHOR]

In the last decades, the attention for pollutant emissions in the civil air transport field has grown up continuously. Especially considering the performances of current turbofan engines, even a modest increase in overall efficiency can lead to great benefits in terms of emissions reduction. Therefore, dedicated performance prediction tools are mandatory in order to carry out an estimation of such outputs. The aim of the present study is to develop a procedure devoted to a preliminary output prediction of an aero engine for civil transportation and an uncertainty quantification analysis based on main performance parameters. For the first step, following the strategy already adopted in previous work on this topic [1], the GEnX, a high-bypass turbofan engine, has been considered as the reference cases. The main design characteristics available from the constructor for this engine have been employed to model the engine with a 0-D numerical tool (ESMS), developed by the University of Florence [2]. Great efforts have been required in the modelling of the GE9X engine since few technical data are available currently. The estimated engine performances have been compared in the LTO cycle with the official data coming from ICAO [3], showing a good agreement. The second step, involving the UQ analysis, takes into consideration 4 specific input parameters that mainly affect the modelling and, thus, the performance outputs, of the engine. BPR, inlet massflow, fuel massflow and isentropic efficiency of the components are taken into consideration. A recently developed Uncertainty Quantification (UQ) methodology using DAKOTA have been employed in order to outline the results: thrust and T49 have been considered. Moreover, a sensitivity through Sobol’s indices has been carried out in order to seek the most influencing parameters. More in detail, a polynomial chaos approach has been adopted. This numerical approach gives very accurate results, comparable to a Monte Carlo analysis, with a remarkable drop in term of computational effort required: only 16 evaluations are required in order to carry out a complete uncertainty analysis. Results will show how the efficiency dominates for the thrust whereas a more balanced situation is estimated for the T49. [ABSTRACT FROM AUTHOR]

Recently, there has been growing interest in outer-space rocket launch systems with a renewable first stage. One of the promising options for such a scheme is an air launch system when a rocket rises into the stratosphere by the aircraft. At the same time, the aircraft needs an environmental control system for the cockpit and auxiliary environmental controlled compartments. To increase the payload of an aircraft, it is interesting to consider options for an environmental control system (ECS) without air sampling from aircraft engines. In this case, the option of using vapor compression cooling is interesting, and in this situation, the ECS turbo compressor does not need to increase the air pressure up to several atmospheres - but only to a value of about one atmosphere. In this paper, we consider a progressive method for designing a turbo compressor impeller. In using the proposed ECS scheme, the energy consumption for the needs of the environmental control system is reduced when parking in summer on the ground by 10 times, in cruise flight by 16.6 times. As a result of comparing the calculations of the turbo generator, performed according to the classical methodology and performed during modeling, it was revealed that using the same initial data, different impeller geometry is obtained. This may be due to the fact that the simulation takes into account the reality of the properties of the working gas and more accurately takes into account the internal leakage of gas from the region of high pressure to low. [ABSTRACT FROM AUTHOR]

Functionally graded materials (FGMs) are the advanced form of composite materials. They possess specific properties in unidirection or bidirection according to some mathematical models available in the literature. FGM structures are being explored in various engineering applications such as beam type structures are most commonly used in airplane propeller blades, robot arms, turbine vanes and astronomical erectable bangs etc. Plate type structures are particularly used in defense sector as penetration resilient resources for manufacturing of ammunition - resistant vests and armour plates. Shell type structures are used in manufacturing of load bearing components for aircrafts, ships, buildings and some parts of space launcher transport systems. This paper presents a broad discussion on vibration analysis of different types of structures i.e. beam, plate (circular, annular, rectangular, square, trapezoidal, skew) and shell (cylindrical, conical and spherical), which can be useful in the design of FGM modelling. This review paper is a collection of material based on vibration analysis of different FGM structures (beam, plate and shell) used in various advanced engineering fields. Further, this paper is categorized on the basis of modal behavior of FGM structures under with or without thermal effect. [ABSTRACT FROM AUTHOR]

This work is dedicated to the transformation of aviation turboprop engine AI-24 for energy purposes. The paper provides an analysis of engine construction, design modifications analysis of main components for energy use, as well as analysis of major engine systems. Thermal cycle engine is calculated for first cruise mode. It also discusses the legislative formalities and requirements associated with aircraft engine modifications for energy purposes. The work is also devoted to analysing the actual state of the engine and its inspection. It is a procedure for checking the actual condition of the air turboshaft engine. In the end, it evaluates the use of motor AI-24 for power generation purposes and proposes the possibilities for solving problems of implementation of aircraft turboprop engines for energy purposes. [ABSTRACT FROM AUTHOR]

Consideration of the influence of vibrations in the study of icing processes is an urgent task for the ground application of aircraft engines and compressors in gas transmittal units in the Far North regions. The article presents the results of physical modeling of icing processes on the wing profile in the energy-efficient small-sized climatic wind tunnel made in the Institute. A comparison is made with the NASA physical experiment data. [ABSTRACT FROM AUTHOR]

Numerical modeling of the icing process on the wing profile NACA 0012 is conducted. The influence of speed, pressure and temperature of the incoming gas-dynamic flow, the attack angle of the profile, the water content of the medium, the wing surface roughness, the profile exposure in the flow on the aerodynamic profile characteristics is studied. The mathematical model is given that takes into account the direct modeling of contours of ice build-up formed as a result of impact of droplets on the wing profile, processes of ice accretion and sublimation, evaporation of a liquid film, transport of liquid along the profile surface. The studies were carried out using the ANSYS engineering analysis system FENSAPICE 3D on a high-performance computing cluster. Research of icing processes is equally important for ground application of aircraft engines and compressors in gas transmittal units in the Far North. [ABSTRACT FROM AUTHOR]

The model of installation for tests of full-scalelinersfor aircraft engines is presented.The sound propagation in ducts of spinning modes generator and the whole installation is simulated based on the solution of the three-dimensional Helmholtz equation by the finite element method. The calculated values of the acoustic pressure were processed by the method of cross-correlation with reference channel. The extracted spinning modes were compared with the numbers of the generated modes. The obtained results confirmed the possibility of the designed installation to generate spinning modes with given numbers. The proposed approach can be used in the design problems of spinning modes generators for experimental studies of full-scale liners, as well as the development of techniques for the liner impedance eduction and determining the modal composition of the noise propagating in aduct. [ABSTRACT FROM AUTHOR]

To ensure contactless sealing of the connection between the rotating rotor and the stationary body in aircraft engines [16], high pressure pumps [13, 14], etc., labyrinth seals (LS) are used. In labyrinth seals, the working medium is sealed by throttling it when moving through successive constrictions and expansions. The study of throttling is usually performed when investigating the gas flow in the direction parallel to the rotor axis. However, it was shown in [1] that the wave processes occurring in the circumferential direction of the labyrinth seals during the vibrations of the rotor contribute to the formation of gas dynamic oscillatory processes. It should be noted that sequencing of the constrictions and extensions affects the oscillation amplitude in the gas-dynamic cavity between the LS and the rotor and increases the flow unevenness. Consequently, if these elements are not taken into account in aeroelastic calculation [15, 21] it can give an additional margin of reducing oscillations in LS and, which is important, to solve related problems [18] of continuous media mechanics [19], reduce labor intensity and counting time. Thus, in accordance with the foregoing, the LS calculation is replaced with calculating the gap seal, equivalent (with margin) to the labyrinth seal, if we consider the processes occurring in the LS circumferential direction. [ABSTRACT FROM AUTHOR]

The paper deals with a fuel mass flow rate controller with indirect action for aircraft jet engines. The author has identified fuel controller's main parts and its operation mode, then, based on these observations, one has determined motion equations of each main part, which have built system's non-linear mathematical model. In order to realize a better study this model was linearised (using the finite differences method) and then a dimensionalized. Based on this new form of the mathematical model, after applying Laplace transformation, the embedded system (controller+engine) was described by the block diagram with transfer functions. Some Simulink-Matlab simulations were performed, concerning system's time behavior for step input, which lead to some useful conclusions and extension possibilities. [ABSTRACT FROM AUTHOR]

Aviation affects the environment via the emission of pollutants from aircraft, impacting human health and ecosystem. Impacts of aircraft operations at lower ground towards local air quality have been recognized. Consequently, various standards and regulations have been introduced to address the related emissions. This paper discussed both environmental regulations by focusing more on the implementations of LTO emissions charges, an incentive-based regulation introduced in Europe as an effort to fill the gap in addressing the environmental issues related to aviation. [ABSTRACT FROM AUTHOR]

TiAl intermetallic alloys have attracted great interest among aerospace industry after successful utilization in low pressure turbine blades of aircraft engine which makes dramatic weight saving up to 40% weight saving. However, poor oxidation and corrosion resistance at temperatures above 800°C still become the drawbacks of this alloys, making the development of protective coatings to improve the resistance is important. This study investigates the hot corrosion behavior of two phases intermetallic alloy α2-Ti3Al/γ-TiAl with and without enamel coating using immersion test method in molten salt of 85%-wt Na2SO4 and 15%-wt NaCl at 850°C. The results show after 50 hours of hot corrosion test, bare alloy showed poor hot corrosion resistance due to the formation of non-protective Al2O3 + TiO2 mixed scale at the surface of the alloy. Improvement of hot corrosion resistance was obtained in samples protected with enamel coating, indicated by significant decreasing in mass change (mg/cm2) by 98.20%. Enamel coating is expected to has the capability in suppressing the diffusion of oxygen and corrosive ions into the substrate layer, and consequently, it improves hot corrosion resistance of the alloy. The study showed that enamel coatings have strong adherent to the substrate and no spallation was observed after hot corrosion test. Nevertheless, the dissolution of oxides components of the enamel coating into the molten salts was observed that lead enamel coating degradation. This degradation is believed involving Cl- anion penetration into the substrate through voids in the coating that accelerates the corrosion of the two phases α2-Ti3Al/γ-TiAl alloy. Even though further observations are needed, it appears that enamel coating could be a promising protective coating to increase hot corrosion resistance of TiAl intermetallic alloys. [ABSTRACT FROM AUTHOR]

The present work is devoted to the detailed stress-strain analysis of the composite outlet guide vane (OGV) for aircraft engines with a special focus on areas with twisted layers where the initiation of high interlaminar stresses is most expected. Various polymer composite materials and reinforcing schemes are researched. The technological scheme of laying-out of anisotropic plies and the fastening method are taken into account in the model. The numerical simulation is carried out by the finite element method (FEM) with the ANSYS Workbench software. It is shown that interlaminar shear stresses are most dangerous. It is found that balanced carbon fiber reinforced plastic (CFRP) with the [0°/±45°] reinforcing scheme allows us to provide the double strength margin under working loads for the developed OGV. [ABSTRACT FROM AUTHOR]

Modeling massflow-traction characteristics of the power unit (PU) may be of interest in the study of aerodynamic characteristics (ADC) aircraft models with full dynamic likeness, and in the study of the effect of interference PU. These studies require the use of a number of processing methods. These include: 1) The method of delivery of the high-pressure body of jets model engines on the sensitive part of the aerodynamic balance. 2) The method of estimate accuracy and reliability of measurement thrust generated by the jet device. 3) The method of implementation of the simulator SU in modeling the external contours of the nacelle, and the conditions at the inlet and outlet. 4) The method of determining the traction simulator PU. 5) The method of determining the interference effect from the work of power unit on the ADC of model. 6) The method of producing hot jets of jet engines. The paper examines implemented in ITAM methodology applied to testing in a supersonic wind tunnel T-313. [ABSTRACT FROM AUTHOR]

This paper examines a simplified mathematical model of the aircraft engine, based on the theory of linear and nonlinear systems. The dynamics of the engine was represented by a linear, time variant model, near a nominal operating point within a finite time interval. The linearized equations were expressed in a matrix form, suitable for the incorporation in the MAPLE program solver. The behavior of the engine was included in terms of variation of the rotational speed following a deflection of the throttle. The engine inlet parameters can cover a wide range of altitude and Mach numbers. [ABSTRACT FROM AUTHOR]

This study explores the dynamic characteristics of the combined aircraft-engine system, based on the general theory of the state variables for linear and nonlinear systems, with details leading first to the separate formulation of the longitudinal and the lateral directional state variable models' followed by the merging of the aircraft and engine models into a single state variable model. The linearized equations were expressed in a matrix form and the engine dynamics was included in terms of variation of thrust following a deflection of the throttle. The linear model of the shaft dynamics for a two-spool jet engine was derived by extending the one-spool model. The results include the discussion of the thrust effect upon the aircraft response when the thrust force associated with the engine has a sizable moment arm with respect to the aircraft center of gravity for creating a compensating moment. [ABSTRACT FROM AUTHOR]

Titanium aircraft engine forgings are inspected at all material depths using the ultrasonic testing (UT) process called multizone inspection. This process creates a raster array of 1D A-Scan signals that image the material's underlying characteristics, which in the case of forged titanium, result in highly variable noise. The 3D volume is analyzed as a stack of 2D depth slices that are gated into C-Scans. The intention is to accept or reject the part by examining for the presence of small anomalies in these images in terms of their signal to noise ratio (SNR). Ultrasonic testing inspectors determine that rejection decision by using specialized image software and a 2D assisted defect recognition (ADR) algorithm. This approach for calculating SNR greatly reduces inspector subjectivity compared to a manual approach, but in 2D, not all available information is used to determine a true detection. Enabling ADR to use the 3D volume for the forging inspection, an automated SNR calculation has been extended to address these issues. The 3D ADR algorithm's life cycle from design to validation will be discussed. Validation testing results have shown that 3D ADR significantly increases probability of detection compared to 2D ADR while also reducing its false positive rate. [ABSTRACT FROM AUTHOR]

In many NDE applications, multiple sources of data are available covering the same region of a part under inspection. These overlapping data can come from intersecting scan patterns, sensors in an array configuration, or repeated inspections at different times. In many cases these data sets are analysed independently, with separate assessments for each channel or data file. It should be possible to improve the overall reliability of the inspection by combining multiple sources of information, simultaneously increasing the Probability of Detection (POD) and decreasing the Probability of False Alarm (PFA). Data registration, i.e. mapping the data to matching coordinates in space, is both an essential prerequisite and a challenging obstacle to this type of data fusion. This paper describes optimization techniques for matching and aligning features in NDE data. Examples from automated ultrasound inspection of aircraft engine discs illustrate the approach. [ABSTRACT FROM AUTHOR]

Aircraft engine turbine blade is the most susceptible part to discontinuities as it works in the extremely high pressure and temperature. Among various types of NDT method, Fluorescent Penetrant Inspection (FPI) is comparably cheap and efficient thus suitable for detecting turbine blade surface discontinuities. In this paper, we have developed an Advanced Automatic Inspection System (AAIS) with Image Processing and Pattern Recognition techniques to aid human inspector. The system can automatically detect, measure and classify the discontinuities from turbine blade FPI images. The tests on the sample images provided by industrial partner have been performed to evaluate the system. [ABSTRACT FROM AUTHOR]

The probability of detection (POD) of inspection techniques is a key input to estimating the lives of structural components such as aircraft engines. This paper describes work conducted as a part of the development of POD curves for the ultrasonic detection of synthetic hard alpha (SHA) inclusions in titanium aircraft engine forgings. The sample upon which the POD curves are to be based contains four types of right circular SHAs that have been embedded in a representative titanium forging, as well as a number of flat bottomed holes (FBHs). The SHAs were of two sizes, [sharp/mesh/hash_synonym]3 and [sharp/mesh/hash_synonym]5, with each size including seeds with nominal nitrogen concentrations of both 3 and 17 wt. %. The FBHs included sizes of [sharp/mesh/hash_synonym]1, [sharp/mesh/hash_synonym]3, and [sharp/mesh/hash_synonym]5. This discreteness of the data poses a number of challenges to standard processes for determining POD. For example, at each concentration of nitrogen, there are only two sizes, with 10 inspection opportunities each. Fully empirical, standard methodologies such as a versus a provide less than an ideal framework for such an analysis. For example, there is no way to describe the beam limiting effect whereby the signal no longer increases the flaw grows larger than the beam, one can only determine POD at the two concentration levels present in the block, and confidence bounds tend to be broad because of the limited data available for each case. In this paper, we will describe strategies involving the use of physics-based models to overcome these difficulties by allowing the data from all reflectors to be analyzed by a single statistical model. Included will be a discussion of the development of the physics-based model, its comparison to the experimental data (obtained at multiple sites with multiple operators) and its implications regarding the statistical analysis, whose details will be given in a separate article by Li et al. in this volume. [ABSTRACT FROM AUTHOR]

Single crystal metal alloys are used extensively in the manufacture of jet engine components for their excellent mechanical properties at elevated temperatures. The increasing use of these materials and demand for longer operational life and improved reliability motivates the requirement to have capable NDE methods available. Ultrasonic arrays are well established at detecting sub-surface defects however these methods are not currently suitable to the inspection of single crystal components due to their high elastic anisotropy causing directional variation in ultrasonic waves. In this paper a model of wave propagation in anisotropic material is used to correct an ultrasonic imaging algorithm and is applied to single crystal test specimens. The orientation of the crystal in a specimen must be known for this corrected-algorithm; therefore a crystal orientation method is also presented that utilizes surface skimming longitudinal waves under a 2D array. The work detailed in this paper allows an ultrasonic 2D array to measure the orientation of a single crystal material and then perform accurate volumetric imaging to detect and size defects. [ABSTRACT FROM AUTHOR]

Synthetic defects are an important tool used for characterizing the performance of nondestructive evaluation techniques. Viscous material-filled synthetic defects were developed for use in vibrothermography (also known as sonic IR) as a tool to improve inspection accuracy and reliability. This paper describes how the heat-generation response of these VMF synthetic defects is similar to the response of real defects. It also shows how VMF defects can be applied to improve inspection accuracy for complex industrial parts and presents a study of their application in an aircraft engine stator vane. [ABSTRACT FROM AUTHOR]

The possibility to use a nuclear reactor for airplanes propulsion was investigated taking in to account 2 possible solutions: the direct cycle (where the fluid pass through the reactor’s core) and the indirect cycle (where the fluid is passing through a heat exchanger). Taking in to account the radioprotection problems, the only realistic solution seems to be the indirect cycle, where the energy transfer should be performed by a heat exchanger that must work at very high speed of the fluid. The heat exchanger will replace the classical burning room. We had performed a more precise theoretical study for the nuclear jet engine regarding the performances of the nuclear reactor, of the heat exchanger and of the jet engine. It was taken in to account that in the moment when the burning room is replaced by a heat exchanger, a new model for gasodynamic process from the engine must be performed. Studies regarding the high flow speed heat transfer were performed. [ABSTRACT FROM AUTHOR]

The working conditions for the aircraft engines components demand a good response of their mechanical properties at high temperatures and aggressive environments. Those challenging conditions force the use of new materials like titanium (and nickel) based alloys, qualified as difficult-to-cut materials due to their low machinability. Among them, the Ti-6Al-4V is very widespread because of its high strength/weight ratio. On the other hand, a very demand task for aeronautical components is the hole making operation, being in most cases, the last performed operation. For this reason, drilling operation is strongly related to the quality and productivity since any machining error could damage the component in the final steps. Thus, drilling operation determines the minimum machining time which is reflected upon the cost per unit. This study focuses the attention on a relative new technique that could replace the conventional drilling resulting in a more added-value operation: ball helical milling (BHM). This new technique and a modified version (CBHM) were compared with a common drilling operation. [ABSTRACT FROM AUTHOR]

For supersonic flows relative to turbo-engine fan blades, measured acoustic spectra near the inlet present tones at fan blade passing frequency (BPF), engine shaft rotation frequency, or Engine Order (EO), and their respective harmonics. The latter are responsible for the Buzz-saw noise and are thus referred to as “Buzz-saw” or “multiple pure” tones. This work first attempts to reformulate McAlpine and Fisher's frequency domain model (2001) for the propagation of a unidimensional sawtooth waveform spiralling inside a hard-walled cylindrical duct in the presence of a uniform flow. The non-dissipative Burgers equation is solved using a shock fitting method, and modal attenuation and dispersion are added using a split-step computational method. In practice, shocks do not only occur at blade tips but on a significant portion of the blade span. The plane wave hypothesis being no longer valid, a new three dimensional model is required. This model is based on the computation of the axially varying amplitudes of the modal solutions, in order to take into account the nonlinear modal interactions. [ABSTRACT FROM AUTHOR]

Numerical simulation has become a powerful tool that enables to save costs and time in the design and manufacturing of forged parts for aircraft engines. A complete simulation “package” based on the software code Forge® is used at Snecma to predict the properties of such parts and optimize the manufacturing processes. In order to have a good prediction of the metallurgical and mechanical properties, the simulation of the whole forging process is needed. Until now ring rolling simulation tools have been developed but they still need to be improved. Moreover we have to evaluate these tools before bringing them into production. The aim of this paper is to present the work being done at Snecma on ring rolling simulation. An overview of the complete simulation “package” will first be given. Some tests performed with the ring rolling simulation module in Forge® will be presented, including the comparison between simulation results and real parts. The application to an Inconel® 718 disk will be discussed more into details. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Quasi-one-dimensional analyses with either chemical equilibrium or finite-rate reaction were conducted to evaluate the effects of contamination from vitiation on engine performances, namely thrust production. The incoming flow state was calculated based on measured values, and a higher total enthalpy for the freestream through a vitiation heater compared to that through a storage heater was found, which reduced the thrust production by about 10% in equilibrium case. With finite-rate reaction calculation, possibility of further reduction of the thrust production by about 5% due to contamination effect on combustion mechanism, was found. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The inspection of critical rotating components of aircraft engines has made important advances over the last decade. The development of Phased Array (PA) inspection capability for billet and forging materials used in the manufacturing of critical engine rotating components has been a priority for Honeywell Aerospace. The demonstration of improved PA inspection system sensitivity over what is currently used at the inspection houses is a critical step in the development of this technology and its introduction to the supply base as a production inspection. As described in Part I (in these proceedings), a new phased array transducer was designed and manufactured for optimal inspection of eight inch diameter Ti-6Al-4V billets. After confirming that the transducer was manufactured in accordance with the design specifications a validation study was conducted to assess the sensitivity improvement of the PAI over the current capability of Multi-zone (MZ) inspection. The results of this study confirm the significant (≈ 6 dB in FBH[sharp/mesh/hash_synonym] sensitivity) improvement of the PAI sensitivity over that of MZI. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]