Analytical redundancy of measurement channels in a digital control system of a gas turbine engine based on the adaptive Yazvinsky filter

An algorithmic method is proposed to increase the fault tolerance of digital automatic control systems of gas turbine engines, based on the use of the optimal observer – the adaptive Yazvinsky filter, consistent with the mathematical model of the engine. Simulation of the algorithm was carried out according to flight tests of the PS-90A engine as part of the Tu-214 aircraft in stationary and transient modes of operation.

Keywords: gas turbine engine, automatic control system, analytical redundancy, adaptive Yazvinsky filter

Inozemtsev A.A., Gribkov I.N., Lamanova N.G., Pleshivikh A.S., Sazhenkov A.N.

Features of controlling self-tuning programs during testing of a GTE’s adaptive controller

The features of determining a GTE’s adaptive controller characteristics (self-tuning programs) are discussed, taking into account the dependence of their parameters on the testing signal. Organization of the adaptive controller testing in the frequency domain is proposed to verify the compliance of its self-tuning programs. It was possible to acquire stable estimates of the parameters during the experiment even with measurement noise using a digital correlation filter of signals to identify the parameters of self-tuning programs’ mathematical models. D-optimal experimental design was applied to reduce the experiment volume and the costs of its implementation. The effec­tiveness of the proposed approach was verified by testing a demonstration sample of a gas turbine engine’s adaptive temperature controller.

Keywords: gas turbine engine, automatic control system, adaptive controller, self-tuning program, design of an experiment

Kesselman M.G.

Conceptual design of a brush seal assembly for an aircraft turbofan

The results of the computational study of the brush seal leakage are presented with varying porosity and thickness of the brush, diameter of the bristles, and the number of seals. The study also takes into account changes in the assembly’s radial clearance (interference fit) during operation according to the model cycle. It is demonstrated that the brush seal’s leakage characteristic degrades with time as a result of bristle wear. Recommendations are formulated for the use of brush seals as part of the engine, including requirements for their design and the range of rational changes in the main parameters.

Keywords: brush seal, leakage, radial clearance, gas turbine engine, mathematical simulation

Temis Yu.M., Selivanov A.V.

Reduction of a counter-rotating fan tone noise at the Approach operational conditions by increasing the axial spacing

The main noise source in a counter-rotating fan is the rotor-rotor interaction. Its power depends significantly on sizes of the axial spacing. Therefore, one of the ways for improving acoustics of the counter-rotating fan is an increase in the axial spacing between blade rows. This work presents a computational study of aerodynamic and acoustic characteristics of two variants of a model counter-rotating fan for turbofan engines with an ultra-high bypass ratio, which have various axial spacings. The study aims to estimate the difference in acoustic performance that could be achieved by increasing the axial spacing as well as the effect of such changes in the fan design on aerodynamic characteristics. As shown, it is possible to achieve a noticeable fan tone noise reduction at the Approach operational conditions without a considerable decrease in the fan aerodynamic performance at design point.

Keywords: counter-rotating fan, tone noise, aeroacoustics

Druzhinin I.M., Mileshin V.I., Rossikhin A.A.

Verification of the isotropy postulate during deformation of aluminum alloy V95 along straight strain trajectories with a break angle of 135 degrees

The paper presents results of two experiments to verify the isotropy postulate under complex loading of the V95 aluminum alloy (7075), which is sensitive to the type of stress state. Experimental studies were carried out on the SN-EVM test unit on thin-walled tubular specimens during their deformation along two-link strain trajectories with break angles of 135°. The experimental programs were implemented in the deviatoric strain plane Э1–Э3 with simultaneous combined action of axial force and torque on tubular specimens (Р–М experiments, kinematic loading). The scalar and vector properties of the V95 alloy have been studied.

Keywords: plasticity, complex loading, isotropy postulate, scalar material properties, vector material properties, experiment, strain trajectory, V95 alloy

Zubchaninov V.G., Gultyaev V.I., Alekseev A.A., Savrasov I.A., Subbotin S.L., Garanikov V.V.

Experience and prospects of using cryogenic and gas-composite fuels

The paper describes advantages and disadvantages of cryogenic and gas-composite fuels compared to hydrocarbon fuels. The experience of using cryogenic fuels in aviation GTEs and ground-based GTUs by domestic and foreign enterprises is presented. Design features of aircraft and propulsion systems operating on cryogenic fuel are high­lighted, which must be taken into account during their design and operation. Future prospects and beneficial effects of the gradual transition to hydrogen fuel are illustrated.

Keywords: gas turbine engine, cryogenic fuel, methane-hydrogen mixture, exhaust emissions

Fedorchenko D.G., Tsybizov Yu.I., Vorotyntsev I.E.

Synthetic hydrocarbon fuels: technological advancements, issues and potential for use in aviation GTEs

The article examines trends in the development of subsonic jet aircraft related to the application of synthetic hydrocarbon aviation fuels for the issue of air transport decarbonization. An overview of the manufacturing technologies for synthetic aviation fuels certified according to the ASTM D4054 standard is presented. Some aspects of using synthetic aviation fuels in GTEs are analyzed. The rationale for carrying out a thorough investigation into combustion characteristics of synthetic fuels is provided, along with recommendations for modeling their surrogates and developing reaction kinetic models of ignition and combustion of synthetic fuel vapors mixed with air.

Keywords: jet aircraft, gas turbine engine, alternative fuel, combustion characteristics, combustion model, emissions

Savelyev A.M., Savelyeva V.A., Kadochnikov I.N., Kozlov V.E., Kostritsa S.A., Novakovskiy D.V.

Some issues related to the emission of non-volatile particulate matter and smoke by aircraft turbofan engines

This article briefly reviews the ICAO standards for non-volatile particulate matter (nvPM) emissions and smoke for aircraft turbofan engines. A comparative analysis of the standards for nvPM and smoke is given, and various formulas for the physical relationship between the concentration of nvPM and the smoke parameter SN are considered. Experimental data on nvPM and smoke produced by modern foreign engines and their compliance with ICAO standards are considered. An analysis of the influence of various parameters on smoke emissions by modern engines was carried out. The issue of nvPM particle size is considered and a proposal is made for the particle size distribution function.

Keywords: emissions, non-volatile particulate matter, smoke, ICAO standards, particle size

Vasiliev А.Yu., Strokin V.N., Shilova Т.V.