Analysis of the influence of the initial requirements for a new generation supersonic civil aircraft on the list of critical technologies

Using the example of two designs of supersonic civil aircraft propulsion systems, differing in the value of the bypass ratio, their design and scheme differences are shown, as well as the impact of these differences on the list of critical technologies necessary for testing to ensure the creation of a new generation supersonic civil aircraft.

Keywords: supersonic civil aircraft, propulsion system, turbofan engine, critical technology, engine component demonstrator

Alendar’ A.D., Grunin A.N., Lukovnikov A.V., Evstigneev A.A., Lanshin A.I., Polev A.S.

Analysis of the stress-strain states of rotor components of a supersonic civil aircraft’s GTE based on a thermomechanical model

A comparative study of the thermal and stress-strain states of GTE cores has been conducted using a thermo­mechanical model. Engine cores for subsonic mainline aircraft (MA) and supersonic transport (SST) are examined considering differences in their flight cycles. The engine cores were designed according to a common layout, with variations in the air systems, in order to investigate the possibility of creating an engine core for SST engine technology demonstrator using the most comprehensive set of components and assemblies that have been developed for the MA engine. Two-dimensional thermomechanical models were developed, which differ in terms of the organi­zation of secondary flows in the air system and the thermal state of the discs. The analysis of the unsteady thermal and stress-strain state was performed, and estimates of durability were provided for the most loaded components of the engine’s core – rotor discs. The kinetics of the radial clearance between the rotor blades and the casing were analyzed for various flight cycles.

Keywords: supersonic transport, mainline aircraft, engine core, thermomechanical model, stress-strain state, radial clearance, durability

Temis Yu.M., Temis M.Yu., Yakushev D.A., Steshakov E.G., Drozhzhin M.V.

Trends in the development of oxygen-hydrogen liquid rocket engines turbopump units

The article focuses on the analysis of parameters that determine the operability of turbopump unit (TPU) designs and the analysis of trends in their development. The pressure at the pump outlets directly influences the pressure in the combustion chamber. Thus, for a given thrust and specific impulse, the pressure determines the dimensions and weight of the combustion chamber, which in turn determine the dimensions and weight of the entire engine. Errors in selecting the layout and parameters for the fuel supply system during the conceptualization stage have led to significant costs in redesigning, manufacturing, and testing. Due to the fact that oxygen-hydrogen rocket engines represent rocket engines with highest stress levels, an analysis of trends in the development of the main component of the fuel supply system, the TPU, was conducted using their example. When conducting the analysis, the following key parameters were used to assess the stress and structural perfection of the unit: pressure at the pump outlets, circumferential velocity at the outer impeller diameter, circumferential velocity at the average turbine diameter, bearing specific speed, gas temperature at the turbine inlet, and mass-to-power ratio of the TPU.

Keywords: liquid rocket engine, turbopump unit, pressure, temperature, circumferential velocity, bearing specific speed, mass-to-power ratio

Ivanov A.V.

Estimation of the error in determining the value of the adiabatic efficiency of a low-pressure fan with no booster stages

The study focuses on the methods of experimentally determining the adiabatic efficiency of a single-stage low-pressure fan in a high-bypass turbojet engine. Two methods for estimating instrumental error while determining the efficiency are presented: 1) based on the measurements of the total pressure and temperature of the flow stagnation at the inlet and outlet of the fan stage, and 2) based on the measurements of the torque and rotational velocity of the power transmission shaft, mass air flow, total pressure and temperature of the flow stagnation in the measuring manifold and at the fan inlet, as well as total pressure at the fan outlet.

Keywords: testing, compressor test facility, fan, torque, mass air flow, efficiency, measurement error

Klinskiy B.M.

Development of physical and mathematical models of volcanic ash accumulation on turbine blades in aviation engines

The most significant impact of volcanic ash on aviation gas turbine engines is the formation of glassy deposits on the turbine’s first-stage guide vanes, which can lead to surges and engine shutdown during flight. The paper introduces, for the first time, a physical model that reflects all the main stages of ash formation and accumulation. Based on the developed physical model, a probabilistic method has been developed for calculating the mass of ash deposits and the areas of volcanic ash accumulation in a turbine. A comparison has been made between the results of modeling and field-testing of the PD-14 engine in compliance with EASA CS-E 1050 in terms of its performance while exposed to volcanic ash. The convergence between the results is satisfactory.

Keywords: volcanic ash, engine flowpath, ash deposits, glassy deposits, mathematical model, aviation safety

Popova D.D.

Applying direct current potential drop method to ascertain fatigue crack growth rate in compact metal alloy specimens for aviation gas turbine engines

Tests were carried out on the fatigue crack growth rate of compact specimens made of titanium and nickel alloys under cyclic loading with the measurement of crack length by the direct current potential drop method and the crack compliance method using a crack opening extensometer. Based on the obtained test results, the parameters of the Paris equation describing the second section of the kinetic diagram of the steady growth of the fatigue crack were determined. The test results obtained through the potential drop method and the crack compliance method were compared. It was established that both methods can be equally effective in determining the fatigue crack growth rate on compact specimens of nickel and titanium alloys.

Keywords: fatigue crack, fatigue crack growth rate, FCGR tests, compact specimen, Paris equation parameters, fatigue crack length, potential drop method, crack compliance method

Volkov M.E., Emmaussky N.M., Khudyakova A.D., Titov V.N., Bychkov P.E., Melnikov S.G.

Methods of experimental determination of the thermal fatigue resistance of heat-resistant alloys (a review)

An overview of experimental methods for evaluating the resistance of heat-resistant alloys to thermal fatigue is presented. These methods allow for the calculation of the durability and strength margins of gas turbine engine components under thermocyclic operating conditions. These methods include bench testing, the Coffin method, and the method developed by NPO CKTI. The advantages and disadvantages of each method are considered.

Keywords: thermal fatigue, blade, disc, sample, number of cycles to failure, viscoelastic plasticity model, deformation range, thermal conductivity

Getsov L.B.

Adaptation of the return-mapping algorithm to the Hosford yield criterion

A brief review of studies on the application of intermediate yield criteria concluded between the Tresca, von Mises and Ishlinsky – Hill criteria, in particular the Hosford yield criterion, is performed. It is shown, that it is necessary to take into account third deviatoric stress invariants for realization of Hosford yield criterion. Consequently, the elastic predictor/plastic corrector algorithm with return to the yield surface, implemented according to an implicit scheme, is adapted to yield surfaces containing both the second and the third deviatoric stress invariants. The paper presents a comparison of the results of numerical modeling using Hosford yield surface with an analytical solution obtained for a continuous rotating disk of constant thickness under bilinear hardening with a Tresca yield surface.

Keywords: Hosford yield criterion, plastic flow, third invariant, rotating disk, return-mapping algorithm

Khudyakova A.D., Sapronov D.V., Kuryshev I.M.