Characteristics Of Gas Turbine Engine Research Articles

The effect of conditions of directional crystallization on the structure of cast blades made of nickel superalloys

The characteristics of gas turbine engines depend on the structural state of the material of the turbine blades and are largely determined by the technology of their manufacture. Identification of the specific defects of casting is an important goal aimed at improving the quality of blade castings since the castings of turbine blades with a monocrystalline structure made of high-alloyed nickel superalloys (NS) are subject to increased requirements for macro- and microstructure. We present the results of studying the effect of directional crystallization parameters on the morphology of the dendritic structure of NS and their tendency to form casting defects of the single-crystal structure. The structure of alloys in single-crystal blade castings and the effect of technological parameters on the dispersion of the structural components of NS were analyzed upon casting of turbine blades with <001> axial orientation on installations with liquid-metal cooling. It is shown that the parameters of the dendritic cells of castings vary in height from 220 to 330 μg and volume fraction of micropores changes from 0.02 to 0.2%. Electron probe microanalysis revealed that the phase and local elemental compositions of the alloy in the areas of the blade tip and isolated grains are identical. The appearance of isolated grains that violate the monocrystalline structure of castings is observed when the rate of NS cooling decreases. To increase the temperature gradient and reduce the probability of formation of extraneous crystals in castings ahead of the crystallization front, optimized temperature-speed modes of casting and directional crystallization are proposed. The obtained results can be used in the development of temperature-velocity parameters of the process of directional crystallization of blades of promising turbines made of new superalloys.

Devising a method for calculating the turboshaft gas turbine engine performance involving a blade-by-blade description of the multi-stage compressor in a two-dimensional setting

The design and adjustment of modern gas turbine engines significantly rely on the use of numerical research methods. This paper reports a method devised for calculating the thermogasdynamic parameters and characteristics of a turboshaft gas turbine engine. The special feature of a given method is a two-dimensional blade-by-blade description of the compressor in the engine system. Underlying the calculation method is a nonlinear mathematical model that makes it possible to describe the established processes occurring in individual nodes and in the engine in general. To build a mathematical model, a modular principle was chosen, involving the construction of a system of interrelated and coordinated models of nodes and their elements. The approach used in modeling a two-dimensional flow in the compressor makes it possible to estimate by calculation a significant number of parameters that characterize its operation. With the help of the reported method, it is possible to estimate the effect of changing the geometric parameters of the compressor height on the characteristics of the engine. To take into consideration the influence of variable modes of air intake or overflow in various cross-sections along the compressor tract, to determine the effect of the input radial unevenness on the parameters of the compressor and engine in general. To verify the method described, the calculation of thermogasdynamic parameters and throttle characteristics of a single-stage turboshaft gas turbine engine with a 12-stage axial compressor was performed. Comparison of the calculation results with experimental data showed satisfactory convergence. Thus, the standard deviation of the calculation results from the experimental data is 0.45 % for the compressor characteristics, 0.4 % for power, and 0.15 % for specific fuel consumption. Development and improvement of methods for calculating the parameters and characteristics of gas turbine engines make it possible to improve the quality of design and competitiveness of locally-made aircraft engines.

Numerical and Experimental Analysis of Combustion Characteristics of Gas Turbine Engines

Advanced computational fluid dynamics (CFD) methods were used to carry out the numerical analysis. It was created a three-dimensional CFD model to represent the intricate flow and combustion processes inside the gas turbine engine. Fuel injection, combustion kinetics, and the effects of turbulence were all taken into account by the model. In order to analyse several combustion factors, such as temperature distribution, species concentrations, and flame propagation, numerical simulations were run.Experimentation was done in order to verify the numerical results and understand the combustion properties better. To simulate the operational circumstances of a gas turbine engine, a test setup was created. Measurements of combustion parameters, including pressure, temperature, and emissions, were made and compared to the numerical forecasts. The computational model might then be verified and improved as a result.The findings of this study offer insightful information about how gas turbine engines behave during combustion. The temperature distribution, species concentrations, and flame propagation within the engine were all correctly predicted by the numerical models. The experimental observations showed good agreement with the expected values, confirming the accuracy of the numerical model. This thorough examination aids in the comprehension of gas turbine engine combustion processes and can be used as a foundation for future design enhancements and performance enhancements.

The impact of physico-chemical properties of the jet fuel and biofuels on the characteristics of gas-turbine engines

The current development trend of global civil aviation is the growth of passenger and freight traffic, which entails the consumption of jet fuel. Under these conditions, increasing the efficiency of jet fuel used is of great importance. Global energy consumption is constantly growing, and, first of all, the question of diversification of oil resources arises, resources from which the bulk of motor fuels is produced. Other types of raw energy sources (natural gas, coal, bio-mass) currently account for only a small part. However, an analysis of the development of jet fuels indicates that work is underway to obtain these from other sources of raw materials, especially bio-fuels. Much attention is given to obtaining bio-fuels from renewable sources – such as algae. The issue of the mass transition of civil aviation to alternative fuels is complex and requires the solution of intricate technical as well as economic issues. One of these is the assessment of the impact of new fuels on GTE performance. It is important to give an objective and quick assessment of the use of various types of fuels on the main characteristics of the engine – i.e., throttle and high-speed characteristics. In this case, it is necessary to take into account chemical processes in the chemical composition of new types of fuel. To assess the effect of fuels on the characteristics of a gas turbine engine, it is proposed to use a mathematical model that would take into account the main characteristics of the fuel itself. Therefore, the work proposes a mathematical model for calculating the characteristics of a gas turbine engine taking into account changes in the properties of the fuel itself. A comparison is made of the percentage of a mixture of biofuels and JetA1 kerosene, as well as pure JetA1 and TC-1 kerosene. The calculations, according to the proposed model, are consistent with the obtained characteristics of a gas turbine engine in operation when using JetA1 and TC-1 kerosene. Especially valuable are the obtained characteristics of a gas turbine engine depending on a mixture of biofuel and kerosene. It was found that a mixture of biofuel and kerosene changes the physicochemical characteristics of fuel and affects the change in engine thrust and specific fuel consumption. It is shown that depending on the obtained physicochemical properties of a mixture of biofuel and kerosene, it is possible to increase the fuel efficiency and environmental friendliness of the gas turbine engines used.

항공기 가스터빈엔진 터빈블레이드의 고장률 예측에 관한 연구

The purpose of this study is to suggest a method for the efficient preventive maintenance of aircraft gas turbine engine turbine blades. For this study, the types and characteristics of gas turbine engines and its turbine blades were studied, the turbine blade defect types that caused an In-Flight Shut Down(IFSD) were analyzed, the blade failure rate according to the blade life cycle was analyzed through the Weibull distribution, one of the statistical techniques. Through these research results, it is possible to supplement the problems of the life cycle management and maintenance method of the turbine blade, and to suggest the measures to strengthen the preventive maintenance of the turbine blade. In this analysis, when total cycle of turbine blade exceeds 18,000 cycles, the failure rate is over 98%, and then the special management measures are required.

Efficiency of application of direct-drive circuit for improvement of starting characteristics of gas turbine engine

The effectiveness of measures to improve the starting characteristics of gas turbine engines (GTE) is considered. To improve the reliability of the GTE launch, it is proposed to use the so-called gearless GTE scheme, created for a “more electric aircraft”, which uses an integrated high-speed starter generator and electric drive units for fuel, oil and other life support of gas turbine engines. With the help of a nonlinear dynamic mathematical startup model, the effect of the magnitude of the given moment of inertia of the rotor on the starting characteristics of the gas turbine engine is evaluated. Change it in the direction of reduction was carried out by replacing the gearbox with attachments to one unit a high-speed starter-generator, installed coaxially with the rotor. Determination of the value of the given moment of inertia of the rotor, aggregates, bearings was carried out using the developed 3-DCAD-models. In the mathematical model of start-up, the thermal state of the oil system, the mechanical power losses for rotating aggregates, bearings, gears are taken into account. The quantitative dependence of the starting characteristics on the moment of inertia of the GTE rotor and other factors is established. For comparison of the basic APU and APU of the direct-drive circuit simulation of the start in the most stressful operating conditions P H = 101,3 kPa at low negative temperatures t H = -40 °C and under normal conditions P H = 101,3 kPa and t H = +15 °C, for “cold” and “hot” state of the engine before starting was made. The tendencies of the moment of inertia of the rotors of the executed and newly created GTE are analyzed. It is shown that the gearless APU in comparison with the basic APU due to the reduction of the moment of inertia by 9,68 % and the reduction of the oil pumped volume in the oil system has a significant improvement in the launch characteristics under ground launch conditions ( P H = 101,3 kPa).

Application of neural network approximation methods in the generalization and presentation of the aircraft gas turbine engine turbomachinery characteristics

A technique of generalizing and representing the characteristics of gas turbine engine (GTE) compressor and turbine using the neural network approximation methods is given. The algorithm of generalizing the experimental performance in mathematical packages on methods of artificial neural networks is shown. Results of approximating and interpolating the characteristics with the use of neural networks based on a multilayer perceptron with different estimated values of π c * and π t * are compared.

The technique for reconciling the dynamic characteristics of gas turbine engines and fuel automatics

The paper presents the technique for matching the dynamic characteristics of gas turbine engines and fuel systems for the unhuman vehicle, described by its logic and graphically illustrates the relationship of the dynamic characteristics of the gas turbine engine, the acceleration path, depending on the frequency of the rotor of the turbocharger rotation time and, depending on the fuel consumption speed.

Diagnosing Propulsion Systems of a Vessels in Varying Marine Conditions

The paper presents some problems of carrying out measurements of energetic characteristics and vessels performance in the conditions of sea examinations. We present the influence of external conditions in the change of vessels hull resistance and propeller characteristics as well as the influence of weather conditions in the results of examinations and characteristics of gas turbine engine. We also discuss the manner of reducing the results of measurements to the standard conditions. We present the way of preparing propulsion characteristics and the analysis of examination uncertainty for the measurement of torque.

ГАЗОТУРБІННИЙ ДВИГУН НА БІОГАЗІ

Розглянуто проблему застосування біопалива для установок великої потужності.Показано, що використання біогазових установок малої та середньої потужностіпояснюється великою кількістю підприємств, у процесі своєї діяльності яких утворюютьсявідносно невеликі об’єми біосубстратів. Для підприємств із великим об’ємом субстратіввикористання модульних систем біогазових установок середньої потужності неефективно.Проаналізовано застосування проблеми технології біогазу та біометану як палива длягазотурбінного двигуна. Визначено рентабельність біогазотурбінної установки зурахуванням робочих характеристик двигуна потужністю 5 МВт, орієнтовної ринковоїціни на природній газ та обладнання компанії «Зорг Україна». Обґрунтовано необхідністьдослідження впливу біогазу на робочі характеристики газотурбінних двигунів та їхнадійності, а також конструювання сучасних вітчизняних систем очищення біогазу.Ключові слова: альтернативні джерела енергії, біогаз, біометан, біопаливо,газотурбінна установка, газотурбінний двигун, установки великої потужності.

Heat-resistant eutectic alloys with carbide-intermetallic strengthening

Some important characteristics of gas turbine engines (in the first place the thrust and the efficiency) depend on the gas temperature and hence are determined by the service life of the blades. Heat-resistant nickel alloys are used for casting blades that can work at maximum temperatures of 1050–1100°C. However, more efficient engines need materials with a higher operating temperature and high-temperature strength. The work concerns the principles of alloying and structure formation of eutectic heat-resistant alloys on a nickel base with carbide and intermetallic strengthening. Their main mechanical properties at high temperatures are analyzed in comparison with the characteristics of high-temperature single-crystal nickel alloys, and the possibility of using them for casting turbine blades of high-temperature gas-turbine engines is considered.

Metrological support to computerized tests on aircraft gas-turbine engines under transient conditions

Metrological support to data-acquisition systems (DAS) is improtant in providing comparability in the measured characteristics of gas-turbine engines (GTE) during development, routine production, and operation. A basic problem in the dynamic calibration of a means of measurement is to reproduce the test signal. This can be illustrated for laser systems designed for the dynamic calibration of temperature and pressure-measurement channels, which are the most widely used in testing GTE. A laser system is described that enables one to determine the amplitude, phase, transient, and pulse characteristics of thermoanemometers, resistance thermometers, and thermoelectric thermometers, including thin-wire and thin-film components, with various gas flow speeds and temperatures. This apparatus can be used in calibrating thermal transducers at frequencies up to 200 kHz with a basic error of 0.5 dB. The gas speed range is 0-200 m/sec with a maximum gas temperature of 600 degrees K. Laser methods provide dynamic calibration for pressure channels in DAS. Dynamic calibration has been applied to pressure transducers by means of a pulsed laser. The light pulse is supplied to the sensing element and produces the dynamic equivalent of a pressure pulse.

Air Pollution Characteristics of Gas Turbine Engines

The current contribution of gas turbine engines to air pollution is small. Improved control of emissions from other sources, increased use of gas turbines, and changes in gas turbine emission characteristics may cause the air pollution contribution of gas turbines to become more significant. A laboratory model gas turbine combustor was used for investigation of the internal burned gas composition. Of particular concern was nitric oxide. It was found that nitric oxide concentration is controlled by the kinetics of its formation. Evidence of the chemical kinetic behavior of carbon monoxide and unburned hydrocarbons also was obtained.