Vol 17, No 3 (2018)

Full Issue

AIRCRAFT AND SPACE ROCKET ENGINEERING
Mechanical engineer, scientist, teacher. On the occasion of centenary of the birth of I.A. Birger
Nozhnitsky Y.A., Belousov A.I.
Abstract

Isaac Aronovich Birger created a scientific school that had a great impact on the development of Russian aircraft and rocket engine construction, as well as on the training of top-qualification academic personnel. In 1946 I.A. Birger entered Central Institute of Aviation Motors named after P.I. Baranov where he worked for nearly 50 years, passing all the stages – from engineer to the Head of the Department of Strength and the Deputy Head of the Institute. His main scientific and engineering efforts were inextricably connected with the problems of ensuring strength of aircraft and rocket engines. We can distinguish three main directions in I.A. Birger’s scientific activities: 1) investigation in the area of mechanics of deformable bodies determining the strength of parts in new operating conditions; 2) development of general numerical methods of calculating stress and strain in structures; 3) development of methods of calculating strength and oscillations of engine parts with wide use of the results of investigation in the first two directions. The main feature of I.A. Birger’s approach to solving engineering problems consisted in the development of engineering solutions based on consistent application of theoretical methods of mechanics and applied mathematics for vital practical tasks determining the working capacity of a wide variety of structures.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):7-15
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Refining methods of vibration diagnostics of wear of turbo-prop engine differential speed reduction unit gear teeth
Avramenko A.A., Kryuchkov A.N., Plotnikov S.M., Sundukov E.V., Sundukov A.E.
Abstract

The paper presents results of complex research of vibration behavior of the differential reduction gear unit of a turboprop engine on the basis of statistics of products with repaired reduction gears and those placed under repair. The conducted research made it possible to establish the source of resonant oscillations of the compressor design elements leading to their breakage. It is established that this source is determined by the kinematics of the reduction gear unit and is associated with the wear of its gear teeth.  Standards for the intensity of the appropriate discrete component of the reduction gear vibration spectrum and those for the amount of permissible wear are substantiated and established on the basis of the work carried out. A complex of diagnostic parameters of wear based on intensity components of the auto-spectrum and the spectrum of maxima, the depth of amplitude modulation in some narrow-band processes, their characteristics based on the parameters of the current frequency and mutual characteristics was identified. It is shown that for the whole complex of the diagnostic parameters obtained their dependence on the wear value is satisfactorily approximated by a linear characteristic. The obtained results can serve as a basis for the development of a complex of methods of differential reduction gear vibration diagnostics.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):16-26
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Evaluation of turbine rotor blade life taking into account static and thermal cyclic loading
Badamshin I.K.
Abstract

The existing methods of evaluating turbine life, taking into account the effects of static and thermal cyclic loading, are based on experimental data. The need for cost- and labor-intensive experiments makes this approach difficult to apply. This brings up a crucial task of calculating the life of a turbine blade, taking into account the interaction of static and thermal cyclic loading. The classical methods based on the hypothesis of continuity do not allow calculating the strength and thermo-physical properties of a material. This problem is solved by the transition to the models of the behavior of materials from the continuity hypothesis to the account of the inter-atomic forces at the level of an elementary atomic cell. This approach makes it possible to calculate strength, elastic and thermo-physical parameters of structural elements theoretically and semi-empirically. These parameters are used as the initial data in calculating the stress-strain state of gas turbine engine elements. They are required to calculate creep strain semi-empirically. In its turn, the ultimate creep strain is a criterion for both static and thermal cyclic loading, which makes it possible to determine the blade life, taking into account their mutual influence.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):27-35
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Refinement of operable state recovery algorithms for “AIST” small satellites on the basis of telemetric information
Volgin S.S., Salmin V.V., Tkachenko S.I., Tkachenko I.S., Ivanushkin M.A.
Abstract

The article deals with the use of telemetric information, namely data on emergencies, failures and malfunctions occurring on AIST small satellites. These data are used for the refinement of standard algorithms of satellite operable state recovery. To this end, an analysis was made of the accumulated volume of telemetric information, consisting of two stages: searching for parameters exceeding the acceptable limits and establishing the causes of emergencies. A detailed study of the causes and consequences of emergencies made it possible to create two fault trees reflecting the ways of the propagation of failures in the small satellite onboard equipment. The use of fault trees and information on emergencies made it possible to refine the algorithms for the operable state recovery developed at the stage of designing AIST small satellites. Two examples of refined algorithms allowing the recovery of the operable state of small satellites after failure of on-board equipment are given in the article.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):36-43
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Use of phase portraits of hydro-mechanical units for diagnosing aircraft hydraulic systems
Gareyev A.M., Popelnyuk I.A.
Abstract

The article deals with diagnostics of hydraulic systems using phase portraits. A brief review of the existing methods for diagnosing hydraulic units identifying their advantages and disadvantages is given. An approach based on the analysis of dynamic characteristics of a hydraulic system and phase portraits of hydro-mechanical units in their operational and faulty conditions is proposed. As an example, we consider a dynamic model of a simplified hydraulic system consisting of standard components. By adjusting the model parameters characteristic faults typically occurring in operation, such as internal leaks in the pump, contamination of the hydraulic fluid with mechanical impurities, sticking of the valve, etc. were artificially introduced in hydro-mechanical units. A family of phase portraits of a hydraulic system for the operational condition and various faulty ones was constructed. A quantitative estimate of their changes, based on calculating the difference in the areas of the figures restricted by their graphs, is proposed. As a result, it was established that failures and malfunctions introduce changes in the phase portraits of hydro-mechanical units, which makes it possible to apply the proposed approach as a basis for diagnosing the technical condition of hydraulic systems.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):44-55
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Analysis of schemes of correction of dynamic characteristics of acoustic probes for measuring pressure pulsations in a gas turbine engine
Gimadiev A.G., Bystrov N.D., Dyagileva E.S.
Abstract

Gas pressure pulsations are one of the main parameters taken into account in gas turbine engine development. Therefore, special attention is paid to the accuracy of measuring pressure fluctuations. A high temperature of gas flow, sensor’s size limitations in many cases do not allow it to be installed directly at the measurement point. There is a need to connect the sensor to the process using a waveguide channel (waveguide). It is known that resonant oscillations occur in the waveguide, leading to an additional dynamic error of the measuring channel. To improve the accuracy of measuring pressure fluctuations, corrective elements are used. A device consisting of a pressure pulsation sensor, a waveguide connected to the process, and a correction element is called a pressure pulsation probe in technical literature. In foreign and domestic literature there is a large amount of information on probes, but because of the variety of schemes of probe correction selecting those that would provide the required accuracy of measurement of pressure pulsations always poses a challenge. Therefore, taking into account the constant increase in the energy intensity of modern engines, and, accordingly, the increase in the temperature of working media, the authors analyzed the effectiveness of corrective elements on the basis of available patents, articles, and monographs. The article considers hardware and software schemes of correction of dynamic characteristics of acoustic probes based on corrective elements with distributed and lumped parameters. The advantages and disadvantages of the schemes are pointed out. Information on methods of calculating frequency characteristics of probes and their digital correction in the processing of experimental data is presented. The article will be of interest to developers of pressure pulsation probes and engineering and technical workers involved in GTE refinement.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):56-67
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Estimating the efficiency of a bypass turbojet engine on the basis of a serial gas generator as a part of the power plant of a high-altitude unmanned aerial vehicle
Zinenkov Y.V., Lukovnikov A.V., Popov A.V., Nechaev V.N.
Abstract

The article presents the results of solving the problem of defining the engineering concept of a power plant with a bypass turbojet engine based on the gas generator of the serial domestic engine TV7 117 developed by the JSC “UEC-Klimov” for an advanced high-altitude unmanned aerial vehicle. The application of this kind of unmanned aerial vehicle is justified, which determines the relevance of the study. The general statement of the problem is given, where the option of the scheme of a bypass turbojet engine with mixing of the contour flows behind the turbine based on the gas generator of the TV7-117 engine is demonstrated and the essence of the solution of the considered problem is revealed. The authors describe the developed method for determining the optimal parameters of the power plant of a high-altitude unmanned aerial vehicle used in solving the problem. The method includes a universal tool for the calculation and theoretical studies of the system “Aircraft power plant” – a complex mathematical model also constructed by the authors. The vector of the variable parameters of the power plant and unmanned aerial vehicle, as well as the vector of the limited parameters adjustable in the package of constrained and unconstrained multiparametric optimization of IOSO NM 2.0 are presented in the section of the problem statement optimization. In conclusion, special attention is given to the detailed analysis of the results obtained and the conclusions of an advisory nature with a set of characteristics and parameters obtained by calculation for engine options with the original and scaled gas generators of the TV7-117 engine.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):68-79
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Schemes, parameters, work process, characteristics and structure of long-range interception aircraft engines
Kovalev A.V., Sanin V.N., Krivenok A.G., Korolenko V.V.
Abstract

The article presents an analysis of promising directions of improving the design and layout schemes of power plants of modern long-range interception aircraft, related to the implementation of the capabilities of bypass turbojet engines. Research of power plants of unconventional design-layout schemes opens significant prospects for improving flight performance of the long-range intercept aviation systems. These are primarily engines with variable parameters of the work process due to wider control of the elements in the flow passage. In engines with variable parameters the elements of the flow duct – compressor guide vanes, turbine nozzle guide vanes, the exhaust system, the combustion chamber and other elements are controlled. Additional components are used that can be switched off or over during the operation of the power plant (combustion chambers in the bypass duct, bypass valves, turbofan adapters), which ensures the adaptation of the engine operation mode to the flight conditions due to the integrated control system adapted to possible failures and malfunctions. It is expedient to use the range of the interception line in the case of a typical flight profile and providing the specified values of the maximum flight speed and altitude as a criterion of efficiency. It is shown that the computational methods based on mathematical modeling are an effective tool for justifying the decision-making in choosing rational values of the parameters of the work process of aviation gas turbine engines.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):80-92
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Development of a procedure for the synthesis of a micro gas turbine engine neural controller with account for fuel consumption constraints
Kuznetsov A.V., Makaryants G.M.
Abstract

Neural networks are often used to model dynamic processes in objects and to synthesize their control systems. However, their application in real systems is now rather limited due to insufficient research into the process of creating control systems. The issues of creating neural network control systems for gas turbine engines, taking into account both their nonlinear dynamics and the fuel consumption constraints depending on the engine operating mode, remain practically unexplored. To take into account the fuel consumption constraints, a method was developed for modifying the misalignment between the actual and target RPM values during the training of the neural controller. The resulting neural controller is characterized by implicit fuel consumption constraints and non-linear dynamics of the engine itself. The developed method for modifying the neural network training error allows one to synthesize a nonlinear control system, taking into account the requirements for limitations in the automatic mode.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):93-102
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Choosing the mixing pattern for oxygen-hydrogen low-thrust rocket engines
Ryzhkov V.V., Morozov I.I.
Abstract

 

The article presents the results of comparison of computation data on the energy parameters of the working process of engines and the thermal condition of the structure obtained for low-thrust rocket engines fueled by gaseous oxygen-hydrogen, using various schemes of mixture formation. The analysis of the efficiency of the working process is carried out on the basis of the patterns of distribution of combustion products temperature in the cross sections of combustion chambers, temperature diagrams, their values in the area of the engine chamber wall and the specific thrust impulse. It is shown that the chosen tools fully characterize the efficiency of the working process implemented in various schemes of mixing in engines and make it possible to assess the quality of a particular scheme. It was found that for most of the parameters used and additional criteria for evaluating the efficiency of the mixture formation scheme for low-thrust rocket engines, the scheme implementing a rotational coaxial multistage flow of gaseous fuel components in the chamber is preferable.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):103-115
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Procedure and mathematical models for the validation of requirements to combat aircraft with account of ensuring its survivability and damage tolerance on exposure to means of destruction
Sazhin A.N., Kovalchuk D.V., Kolodezhnov V.N., Malyshev V.A., Shatovkin R.R.
Abstract

The necessity of creating a complex of mathematical models of the functioning of a combat plane in conditions of exposure to means of destruction to resolve the possible inconsistency of the plane’s tactical flight properties and performance characteristics is validated in the article. The developed scheme of the procedure of assessing the impact of weapons on the aircraft is presented. The scheme allows justification of the design and layout solutions and circuitry to ensure combat survivability, research and analysis of the damage tolerance of the airframe elements under various conditions of the weapon-aircraft rendezvous, including the early stages of design. The principles underlying the development of mathematical models for the formation of the spatial-geometric structure of the aircraft on the basis of its three-dimensional solid-state configuration, simulation of the weapon warhead detonation with the formation of the field of damage agents, aircraft coverage with damage agents with the definition of the facts of their hitting the aircraft are outlined. The technique makes it possible to produce multiple statistical modeling of the process of impact of standard means of destruction on the aircraft with the assessment of characteristics of combat damage of the airframe structures. The individual kinematic characteristics of each damage agent of the weapon warhead in the contact with the elements of the aircraft structure, taking into account the mass and aerodynamic forces are calculated. Examples of the developed mathematical models are given.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):116-126
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Engines for domestic drones: past, present and future
Cherkasov A.N., Legkonogikh D.S., Zinenkov Y.V., Panov S.Y.
Abstract

The article provides an analytical overview of previously created engines, those in operational service and engines being developed for unmanned military-purpose aerial vehicles. The current state of the engine fleet, modern problems of development and production of domestic engines are described. It is shown that modern unmanned military-purpose aerial vehicles use a variety of types of power plants, for which their main technical characteristics, design and layout schemes are given. Some projects carried out under the program of import substitution are disclosed. The results of work conducted at the Department of Aircraft Engines of the Air Force Academy named after Professor N.E. Zhukovsky and Y.A. Gagarin are presented. The article outlines critical technologies for creating full-size gas turbine engines for the most complex and expensive class of heavy unmanned combat air vehicles with a take-off weight of more than 10 tons, designed to solve a wide range of tasks, including strategic ones. On the basis of the analysis of the existing unmanned systems conclusions were drawn as to the choice of the type of engine depending on their take-off weight. The basic directions of further development of power plants for one of the most dynamically developing branches of aviation – unmanned air vehicles - were forecast.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):127-137
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MECHANICAL ENGINEERING
Residual stress optimization of technological processes with the aim of ensuring adhesion of nickel or chromium coatings on parts made of titanium alloys
Bukaty A.S.
Abstract

Work on ensuring adhesion of chromium coating on parts “piston with a rod” made of ВТ3-1, ВТ22 titanium alloys was carried out based on the examination of residual stresses. Ensuring the adhesion of coats was conducted in two stages: at the first stage strengthening treatment was used, and at the second stage optimization of grinding conditions by residual stresses was carried out. A method of predicting process-induced residual deformation by equivalent initial stresses is presented. Residual stresses in a surface layer of specimens cut out of the strengthened parts were studied. It was established that compressive residual stresses in the surface layer ensure the coating adhesion in chromium plating of parts made of titanium alloys. It was shown that ensuring adhesion of coatings on parts made of titanium alloys can be obtained both by strengthening treatment and without it, due to the optimization of grinding conditions. The results obtained made it possible to eliminate surface tempering in the process of grinding parts made of titanium alloys, to ensure  favorable technological heredity not only for the parts under examination, but for other parts such as pistons, hydraulic cylinders and rods.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):138-147
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Dynamics of a dual-mass resonant vibration screen in a first approximation
Dentsov N.N., Koshelev A.V.
Abstract

The decision on creation of a new energy-efficient vibration screen using combination parametrical resonance is presented. The decision makes it possible to expand functional and operational opportunities of vibration machines. Dynamic and mathematical models of a dual-mass resonant vibration screen are presented. Differential equations of the machine motion are given. The principle of work of a resonant vibration screen is described. The trajectory of motion of the center of mass of the system of pendulums of the inertia member of the parametrical drive during their running in on racetracks is given. A method of reducing the data on a dual-mass system to a single-mass one is presented. At the same time an additional condition on the stiffness of elastic members of the oscillatory system is introduced. The value of the coercive force under steady-state resonant oscillations is identified. Ratios between the masses of actuating devices, damping coefficients and linear displacements of the actuating device are obtained. The parametric resonance coupled with the phenomenon of self-synchronization makes it possible to realize self-controlled and self-supported proper motion of the machine. Real samples of dual-mass oscillatory systems with one and two parametrical vibration generators are presented. On the basis of the results obtained for prototypes of a dual-mass system the conclusion about the stability of the resonant operating mode is drawn. The results of this work can be used to produce new highly efficient resonant vibration machines.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):148-157
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Conducting corrosion resistant nickel coating for contacts of the system of aircraft underwater locator beacons
Krivina L.A., Тsareva I.N., Tarasenko Y.P., Fel’ Y.A., Levanov Y.K.
Abstract

The paper deals with the development of manufacturing methods of improving the functionality and reliability of the electric contact made of titanic VT3-1 alloy. This alloy is used in the development of electrical contacts for acoustic beacons used on airplanes of various airline companies. Solving the problem of increasing the life of acoustic beacons (up to 90 days) is directly related to an increase in the stability of the electrochemical characteristics of the contact. To ensure the stable behavior of the electric potential (not more than 0.5 V) at the contact, a method of gas-dynamic spraying of a protective coating based on nickel of increased thickness is proposed. Single-layer and two-layer coatings obtained from different grades of powder mixtures were tested. The regularities of the process of electrochemical breakdown and passivation of protective coatings during comparative short-term tests were studied. Based on the test results, a single-layer gas-dynamic coating of the composition (Ni + Al2O3) formed from the powder mixture of grade N3-00-02 was chosen. The microstructure, phase composition, microhardness, porosity and adhesive strength of Ni-based protective coating were investigated. Electrochemical tests of electrical contact with the investigated coating in the sea water environment depending on the time factor were carried out. Increased thickness of the coatings combined with low open porosity and high adhesive strength provided stable behavior of the electric potential in the process of applying it to the working surface of the titanium alloy contacts VT3-1. This ensures reliable electrochemical protection of contacts in the sea water environment for 90 days.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):158-166
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Shaping technologies for manufacturing noise insulation casings of turbojet engines
Molod M.V., Maksimenkov V.I., Fedoseev V.I.
Abstract

The article discusses questions of shaping honeycomb panels for turbojet engine noise insulation casings. Various types of structures and materials used for manufacturing honeycomb panels are presented. Samples were tested to determine mechanical characteristics. The technology of manufacturing honeycomb panels was determined by the value of relative elongation. The main rejection criteria in forming panels on bending and stretching presses were reviewed. The process of shaping honeycomb panels using computer numerical control (CNC) equipment was analyzed. Force parameters of the shaping process required for the assessment of the stress-strain state and obtaining the control program were determined. The values of the spring action were calculated for single-layer and double-layer panels using the A.A. Ilyushin unloading theorem. It was found that the springing of single-layer and two-layer panels differs due to the magnitude of the generalized rigidity. The value of springing is determined by the known height of the honeycomb panel. Designs of honeycomb panels with different positions of the middle layer along the height of the panel are given. Graphs showing the dependence of the punch radius adjusted for the value of springing on the radius of the part for various types of structures from titanium alloys and stainless steels are presented.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2018;17(3):167-174
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