Digital twin of rig for testing of centrifugal compressor for small-scale gas turbine engine

A digital twin of the rig for testing of centrifugal compressor for small-sized gas turbine engine has been developed. It is used for calculation of changes in clearances in gas-dynamic path of the compressor depending on the design flight cycle. Nominal installation clearances are determined according to calculation results of the compressor aerodynamic design. Clearances changes on design flight cycle were investigated using developed mathematical model of the rig. The mathematical model includes thermohydraulic and thermomechanical models. Coupled calculation of air system and temperature state of test rig is performed by using thermohydraulic model. Thermomechanical model is applied to calculate of deformations and relative displacements of rotor and stator parts in test rig. These deformations are calculated under the action of axisymmetric and nonaxisymmetric loads, including a non-stationary temperature state.Analysis of clearances changes changing has been carried out. Recommendations have been developed to ensure required clearance changes in the compressor at all flight cycle regimes.

Keywords: digital twin, thermohydraulic model, thermomechanical model, kinetics of clearances in gas turbine
engine, centrifugal compressor

Temis Yu.М., Solovjeva A.V., Zhurenkov Yu.N., Startsev A.N., Temis M.Yu., Yakushev D.A., Egorov A.M., Azmetov Kh.Kh., Steshakov E.G., Drozhzhin M.V

Experimental investigations on the effect of slot-type casing treatments with the aim of improvement the aerodynamic and acoustic characteristics of advanced fans

This work aims at optimization of the casing treatment (CT) configuration to simultaneously improve efficiency, a fan’s stall margin, as well as the use of this CT as a reactive type silencer to reduce fan noise. Three versions of a slot-type CT are designed and tested for the model of C179-2 fan used in a bypass engine. The influence of the number of CT rows, geometry of the slots, their relative position and the height of the CT’s annular cavity on the main characteristics of the C179-2 model fan was studied in aerodynamic and acoustic tests. All studied CTs significantly (by 8…16%) increase the fan’s stall margin at moderate and high modes, determined by corrected rotational speed (75…100%), and efficiency increased by 1…2%. Analysis of narrow-band noise spectra and directional patterns showed that the use of this type of CT significantly improves acoustic characteristics of the fan. In total, across to the three certification modes, the sound power of the C179-2 fan model was reduced by 3 dB.

Keywords: casing treatment, acoustic characteristics, noise reduction, aerodynamic characteristics, efficiency, stall margin, advanced fan, bypass engine fan, bypass turbofan engine

Mileshin V.I., Markov S.A., Korzhnev V.N., Khaletskii Yu.D.

Numerical simulation of turbulent combustion of methane-air mixture in moderate Reynolds number conditions

This paper presents the results of direct numerical simulation (3D) of turbulent combustion of a premixed methane-air mixture under model conditions at moderate Reynolds numbers Ret ~ 150 and Karlovitz numbers Ka ~ 5, compares the results obtained in terms of the turbulent flame velocity with one-dimensional calculations according to the mathematical model, as well as the results of well-known empirical generalization formulas and individual experiments. The conditions considered in this work correspond to combustion modes with localization of the main oxidation reactions in a thin region and are close to those realized in model combustion chambers on a premixed mixture. To describe the chemical transformations, the well-known extended kinetic mechanism of methane oxidation, containing 19 components and 83 reactions, was used. Based on the results of direct numerical simulation, the structure of the flame front, its thickness, shape and local curvature are revealed and analyzed.

Keywords: direct numerical simulation, turbulent combustion, turbulent flame velocity, methane-air mixture\

Semenev P.A., Toktaliev P.D.

A modified Walker model for constructing a low cycle fatigue curve with mean strain effect

A modified Walker model for constructing LCF curve with mean strain effect is proposed. The model is a function
that depends on the strain range and the strain ratio controlled during LCF testing of smooth bars. Approbation
and evaluation of the model quality was carried out based on processing the results of strain-life fatigue tests
of bars from titanium alloy Ti-6Al-4V ELI and nickel alloy EI698VD. The proposed model is compared
with Walker's model, which takes into account mean stress effect.

Keywords: low cycle fatigue curve, Walker model, mean strain effect

Servetnik A.N.

Analysis of methods and characteristics of control systems for gas turbines with low-emission combustion chambers

The levels and ranges of emission characteristics of low-emission combustion chambers (MEKS) of gas turbine plants, which implement the technology of combustion of lean, premixed fuel-air mixtures, are considered. The analysis of the design characteristics of the MEKS and the systems used by the world's leading companies for the regulation and maintenance of the specified emission characteristics in the entire range of operating conditions of the gas turbine plant. The results of computational studies of the influence of various control methods on the characteristics of a gas turbine with MEKS are presented. Recommendations are given for the application of control methods depending on the organization schemes of the low-emission process in the gas turbine unit.

Keywords: gas turbine plant, low-emission combustion chamber, single-zone combustion chamber,control system, control methods, emission characteristics, emission of nitrogen oxides, emission of carbon monoxide, efficiency

Sverdlov E.D., Puzich A.A., Dubovitsky A.N., Vladimirov A.V

Review of the works in the USA and Europe on the new generation of aviation complexes and aero engines for their propulsion systems

The current state of the fighter and strike aviation and main directions of works in the USA and Europe
on creation of the 6th generation aviation complexes and engines for their propulsion systems are considered.
It is shown that the 6th generation aviation complexes are likely to include manned and unmanned aerial vehicles
for various purposes, united into a network combat group (platform), which composition may vary depending
on the mission. This group will be able to interact with other military air, sea and land platforms through a secure
network. Coordination and control of individual flying vehicles of the network combat group will be carried
out from the command post – a manned or unmanned 6th generation fighter with a very low level of visibility
and the ability to use new types of weapons, including hypersonic ones. An adaptive engine will be used in the
propulsion system of the advanced fighter, providing them an optimal performance in various flight conditions.

Keywords: aviation complex, aero engine, sixth generation fighter, combat air, critical technologies, propulsion
system, unmanned aerial vehicle

Palkin V.A.

Determination of aerodynamic force in a indoor test cell for testing turbofan engines with high bypass ratio

The method of comparative tests of the reference engine at the outdoor certified test bench and in the (indoor) test cell has been considered for determination of aerodynamic force in the test cell as a correction to the force from the thrust of a turbofan engine with high bypass ratio.

Keywords: bypass turbofan engine, high bypass ratio, bench tests, test bench, outdoor test bench, indoor test cell, test cell, comparative tests, test methodology, aerodynamic certification, test cell certification, reference engine, engine thrust force, external aerodynamic force correction

Klinskiy B.M.