Vol 18, No 3 (2019)

Full Issue

AIRCRAFT AND SPACE ROCKET ENGINEERING
Analytical determination of motion parameters of the center of mass of an uncooperative orbiter on the basis of measurement information provided by on-board systems of a space robot in a coplanar orbit
Ananenko V.M., Golyakov A.D., Kalabin P.V.
Abstract

An analytical solution to the problem of determining the parameters of motion of an orbiter’s center of mass is presented on the basis on the results of measurements carried out using the optical system of a space robot located in orbit coplanar to that of the orbiter. The “space robot-orbiter” line-of-sight angle and the line-of-sight rate in the moving orbital system of coordinates of the space robot are selected as initial parameters that are measured by the space robot’s on-board optical system. Along with the known orbital parameters of the space robot they are used to solve the problem of determining the parameters of motion of the orbiter’s center of mass. When solving this task, assumptions are introduced concerning the central gravitational field of the Earth, the coplanarity of the orbits of the space robot and of the orbiter, absence of influence of the atmosphere, the moon's attraction and the pressure of the solar wind on the motion of the space robot and of the orbiter, absence of errors in the results of measurements performed by the space robot’s on-board optics. Analytical expressions are obtained to determine the unknown parameters of motion of the orbiter’s center of mass. The results presented can be used to develop methods allowing standalone determination of parameters of the orbit of unknown orbiters using on-board optics of a space robot.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2019;18(3):7-15
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Disturbed motion of the hypersonic first stage of an aerospace system in climb
Balakin V.L., Krikunov M.M.
Abstract

Disturbed motion of the hypersonic first stage of an aerospace system in climb is analyzed. Deviations of atmospheric density from standard values and deviations of aerodynamic force coefficients from reference values are taken as disturbances. Disturbance motion of the hypersonic first stage of a hypersonic vehicle with the optimal angle-of-attack schedule obtained for reference atmosphere and nominal aerodynamic characteristics is modeled. Deviations of terminal conditions of disturbed motion from the target values of velocity, altitude and flight path inclination are determined. The problem of minimum propellant mass consumed in the climb with acceleration to hypersonic velocity is solved for disturbed motion by the method of Pontryagin’s maximum principle. Optimal angle-of-attack schedules, optimal flight paths and finite values of the mass of the hypersonic first stage are determined. Comparative analysis of optimal control programs and flight paths for disturbed and undisturbed motion is made.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2019;18(3):16-28
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Selection of project structure for nanosatellite propulsion system
Belokonov I.V., Ivliev A.V., Bogatyrev A.M., Kumarin A.A., Lomaka I.A., Simakov S.P.
Abstract

This paper presents the results of theoretical and experimental research of a prototype of a propulsion system for periodical low-Earth orbit correction of research-and-educational nanosatellites. For that purpose, the prototype is to provide at least 20 m/s relative velocity for a 3U CubeSat with a mass not exceeding 4.5 kg. The personnel and environment safety were taken into account during testing and operation along with the ability to be launched as an associated payload by a “Soyuz”-series launch vehicle or from the ISS. An electro-thermal propulsion system (ResistoJet) was designed with “nonfreezing” mixture of ethanol and distilled water used as the working fluid. It is shown that a standard vehicle power system is capable of initiating one corrective thrust impulse per orbit with flight velocity change of about 0.1 m/s by introducing pulse energy storage units and allocating sufficient time for their charging in the flight profile. The propulsion system prototype was tested in atmospheric conditions. For that purpose shortened “atmospheric” nozzles were used. Testing was carried out using a zero-torque test-bench with high-speed cameras. The measured thrust value was in agreement with the calculated value of 44 mN.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2019;18(3):29-37
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Determining a rational scheme of machining of gas turbine engine essential parts in magnetorheological environments by the method of expert assessment
Boytsov A.G., Kurilovich S.V., Kuritsyna V.V., Siluyanova M.V.
Abstract

The paper examines the basic schemes, features and advantages of magnetic abrasive machining. In this work we provide information on working environments for magnetic abrasive machining, compositions of ferro-abrasive powders and roughness of the surfaces achieved by their application; the process of forming the working layer is also analyzed. A classification of magnetic abrasive machining schemes according to the type of the magnetic inductor used, as well as their advantages and disadvantages are discussed. It is shown that the basic scheme of magnetic abrasive machining, the kind and dispersion of the abrasive medium, are assigned depending on the specific machining conditions and the requirements for the surface layer condition, whereas the choice of the type of the magnetic inductor is not so obvious, since each of the types has its advantages and disadvantages. An expert assessment procedure in choosing an acceptable magnetic-inductor scheme from a number of alternatives for use in magnetic abrasive machining is presented. The method of expert assessment was tested drawing on the example of the work of a group of experts formed by representatives of science and industry. It is shown that the direct-current electromagnetic inductor scheme is a rational scheme of magnetic abrasive machining according to the type of inductor used. This is due to the simplicity of process control and the expansion of technological capabilities, applicability for a wide range of problems solved by magnetic abrasive machining. Permanent-magnet magnetic abrasive schemes can be considered as an alternative to permanent-magnet ones.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2019;18(3):38-47
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Gas dynamic calculation of detonation in constant-cross-section ducts
Grigoriev A.V., Rudakov O.A., Solovieva A.V.
Abstract

The paper presents a computational method with the use of gas-dynamic functions of parameters of detonation in a one-dimensional subsonic flow of ideal gas behind the shock wave propagating in chemically active air-and-fuel mixture in a uniform-cross-section duct, where the resultant of normal pressure forces acting on its side surface is equal to zero. Stabilization of the shock wave is provided by the onset of thermal crisis with the air-and-fuel mixture combustion heat supply to the gas behind the wave. In this case the value of the specific speed of the combustion products is equal to the critical one. The solution of the total-impulse equation considering the above mentioned peculiarities of the flow in a uniform-cross-section duct establishes clear correlation of the specific speed of the stabilized shock wave to the rate of rise of the temperature of the gas behind it, which gives an opportunity to determine all detonation parameters. The shock wave can be initiated by the detonation of an explosive substance and carries a huge amount of energy. It is shown that the shock wave can be obtained only if the source of small disturbances itself moves at the supersonic speed. It is shown that total pressure behind the shock wave decreases significantly and the entropy increases due to the wave losses, whereas the static pressure increases significantly. An explanation of this effect is given. A formula for calculating the rate of gas temperature rise was derived as a function of the specific speed of the shock wave, the air-and-fuel mixture heat value and the heat availability factor that designates the dissociation of the combustion products and heat loss through the duct wall under specified initial conditions. The reliability of the method of calculating detonation was experimentally substantiated. The work is currently important for the evaluation of the detonation engine efficiency.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2019;18(3):48-58
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Choosing the aerodynamic configuration of a subsonic cruise missile
Kovalev M.A., Nikitin A.N.
Abstract

The paper presents a comparison of two aerodynamic configurations of subsonic cruise missiles, characterized by the use of swept-back and forward-swept wings. The results of wind tunnel tests with the use of an automated measurement system characterizing the dependence of the lift and drag coefficients in a sufficiently wide range of angles of attack are presented. This allows us to compare the aerodynamic quality of the cruise missile models under investigation. The analysis of the results of experiments with the models and calculations in conditions of steady-state low-altitude horizontal flight revealed that the configurations of cruise missiles with a moderately swept wing, selected for comparison, have similar aerodynamic characteristics. Both configurations ensure the mode of flight at a given altitude and velocity in the range of the best angles of attack (maximum aerodynamic quality). Missiles with swept-back wings have better aerodynamic performance in terms of maximum aerodynamic quality, while the lift increment due to reduced trim losses for the forward-swept wing configuration only partially compensates the difference of the aerodynamic characteristics of the alternatives under consideration. Therefore, it is concluded that the choice of aerodynamic configuration of a subsonic cruise missile with a swept-back wing is preferable.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2019;18(3):59-66
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Mathematical model for calculating the mass of a heat exchanger in problems of optimizing the parameters of the working process of aircraft gas turbine engines
Kuz'michev V.S., Omar H., Tkachenko A.Y., Bobrik A.A.
Abstract

Despite the fact that aviation gas turbine engines (GTE) have reached a high degree of sophistication, requirements for the improvement of their efficiency are constantly increasing. Reduction of specific fuel consumption and specific weight of the engine unit makes it possible to improve aircraft performance. One of the effective means of reducing specific fuel consumption and obtaining high thermal efficiency of a gas turbine engine is the use of heat recovery, so the interest in it holds throughout the period of development of gas turbine engines. However, the use of heat recovery in aircraft gas turbine engines is faced with a contradiction: on the one hand, heat recovery allows reducing specific fuel consumption, but, on the other hand, it increases the weight of the power plant due to the presence of a heat exchanger. Moreover, with the increase in the degree of regeneration, specific fuel consumption decreases, whereas the mass of the power plant increases.To obtain the desired effect, it is necessary to optimize simultaneously both the parameters of the engine work process and the degree of regeneration of the heat exchanger according to the criteria of evaluating the engine unit in the aircraft system. For this purpose, it is necessary to have a mathematical model for estimating the weight of a highly efficient aircraft heat exchanger. The article presents a developed mathematical model for calculating the weight of a compact plate heat exchanger used to increase the efficiency of a gas turbine engine due to the heating of compressed air entering the combustion chamber by the hot gas that enters the combustion chamber from behind the turbine. We chose a rational pattern of relative motion of the working media in the heat exchanger, the optimal type of plate-type heat transfer surface in terms of minimizing the weight of the heat exchanger and the hydraulic losses in the air and gas ducts. For the selected surface type, the dependence of the specific weight of the heat exchanger on the degree of regeneration is determined for different nozzle exhaust velocities on the basis of a computational algorithm. To assess the reliability of the obtained model, comparative analysis of the effect of the degree of regeneration on the specific weight of the heat exchanger was carried out, based on the comparison of the results of calculations for the developed model with the data of other authors and with the data for the produced regenerators.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2019;18(3):67-80
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Prospects of application of additive technologies to develop parts and components of gas turbine engines and ramjets
Magerramova L.A., Nozhnitsky Y.A., Volkov S.A., Volkov M.E., Chepurnov V.Z., Belov S.V., Verbanov I.S., Zaikin S.V.
Abstract

The possibility of reducing the weight, simplifying the design, reducing the time and cost of development, production and operation are important advantages in the implementation of additive technologies (AT). The use of AT can significantly improve fuel efficiency, environmental and other characteristics of aircraft engines. The possibility of using AT in the production of various parts and components of engines is being currently investigated at CIAM. Examples of these developments, advantages of the use of AT and problems arising in the implementation of these technologies are presented in this article. Models of turbine blades with a highly efficient cooling system, in particular, with penetration cooling were designed and manufactured using optimization methods and taking into account the capabilities of AT. The possibilities of using AT for the manufacture of elements of molds for precision casting of gas turbine engine (GTE) blades of heat-resistant alloys and ceramic rods are shown. Elements of a two-zone front module of the low-emission combustion chamber of an advanced GTE are designed and manufactured using the AT method. Research of prospective branched tree channels of heat exchangers with mutually porous bodies that can be made only by AT methods and the use of which will make it possible to increase the efficiency of heat exchange in the case of lower weight, than that of the structures made by traditional technologies, is being carried out. The AT was used to manufacture complex elements of a ramjet engine. Fire tests of printed sections of the combustion chamber were carried out successfully. Cellular structures to be used in gas turbine engine parts with the aim of reducing their weight were developed. A hollow blade model with cellular-type core was made using AT. Tests of the designed cellular prototypes were carried out. The possibilities of reducing the mass of structural elements using cellular structures obtained by AT methods are shown. Research of hollow disks of turbines and other engine components produced with the aid of AT are carried out. Despite the fact that experimental studies of structural elements obtained by additive technologies have not been completed yet, these works show the prospects for the use of AT in the development of a wide range of engine parts and components.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2019;18(3):81-98
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Method for determination of optimal geometrical parameters of a unit cell of X-shaped truss cores
Mousavi Safavi S.M.
Abstract

Recently, in order to develop high-strength lightweight core materials of sandwich structures for multi-functional applications, a large number of truss structures have been created, including pyramidal and tetrahedral truss cores. In this paper, a new truss structure is developed to be used as core material in sandwich panels. The X-shaped truss core consists of discrete hourglass-shaped unit cells formed by the groove-to-groove connection of two flat X-shaped truss elements made by metal plate cutting. In order to determine optimal geometrical parameters of a unit cell of X-shaped truss core, in this work it is proposed to plot the diagrams of relative density versus the angle of the rods for the required values of equivalent critical compression and lateral shear stresses, and for the required values of equivalent compression and shear stiffness of the unit cell of X-shaped truss core. The results show that with the same mechanical characteristics, the relative density of the optimal X-shaped truss core is less than the relative density of optimal pyramidal and tetrahedral truss cores.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2019;18(3):99-108
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Life of gas turbine engine components under corrosive exposure
Pivovarova M.V., Gladkiy I.L.
Abstract

Currently, operation of gas turbine engines takes place in the aggressive medium of the atmosphere of some climatic regions. As a consequence, this may cause fast degradation of the strength properties of parts of gas turbine equipment and their subsequent premature failure. The problem of determining the life of gas turbine engine components under corrosive exposure is vital. We present an analysis of the state of the art in the field of assessment of gas turbine engine component life under the influence of corrosive environment in Russia and abroad. UEC-Aviadvigatel, FSUE “VIAM” and NPO “TSKTI” JSC formulated approaches to the development of the lifing process for engine parts operating in corrosive environment.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2019;18(3):109-117
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Justification of the architecture of an interactive information model of the process of space-mission vehicle launch preparation
Privalov A.E., Bugaichenko P.Y.
Abstract

The article presents a solution of the problem of substantiating the architecture of an interactive information model for the launch preparation of an integrated launch vehicle (ILV). The relevance of the research is due to the complexity and high dynamics of the ILV launch preparation process, as well as the latest achievements in the field of information modeling and decision support theory. The aim of the research is to raise the situational awareness of the decision maker in managing the process of preparing ILV for launch. The process of formation of situational awareness as an integral part of the decision-making process is analyzed. On the basis of this analysis a model of an indicator of the effectiveness of situational awareness formation is proposed for the first time. A model for evaluating the effectiveness of the process under study is developed on the basis of the mathematical apparatus of the theory of continuous-time Markov chains. The results of numerical experiments confirming the adequacy of the model and making it possible to state the quantitative requirements for the process of formation of situational awareness, ensuring its maximum efficiency, are presented. The tasks of the information system aimed at satisfying the requirements are stated, and the architecture of the information model of the ILV launch preparation process is developed. The research results can be used to justify the quantitative requirements for the developed information models of the launch situation at the stage of development of technical specifications.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2019;18(3):118-130
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Сalculated analysis of the influence of operation and design factors on the parameters of oxygen-hydrogen low-thrust rocket engines
Ryzhkov V.V., Morozov I.I.
Abstract

The paper presents the results of calculating thermodynamic and thermophysical properties of the combustion products of gaseous oxygen-hydrogen fuel according to the ideal LRE model taking into account the phase state of the components, as well as the parameters of a low-thrust engine according to the model of computational gas dynamics to ensure the selection of operation and design factors that define the design of a thruster for advanced aerospace objects. It is shown that ideal models can be used for the selection of some parameters, such as: the excess oxidant ratio, the pressure in the combustion chamber, the geometric degree of area expansion ratio. High-level computational gas dynamics models need to be used for the selection of some of the parameters of the engine to be designed, such as: design parameters of the propellant injection pattern, reduced length of the combustion chamber and some others. Air specific impulse was used as the selection criterion. The obtained calculation data allow one to choose the main parameters of the engine being designed with account for real processes in the combustion chamber and the nozzle of the engine.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2019;18(3):131-142
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Design of experiments for verification of computational life prediction methods
Samsonova O.V., Fetisov K.V., Karpman I.V., Burtseva I.V.
Abstract

The failure of heavily loaded rotating parts of aviation gas turbine engines may bring about dangerous consequences. The life of such parts is limited with the use of computational and experimental methods. Computational life prediction methods that are used without carrying out life-cycle tests of engine parts or assemblies should be substantiated experimentally. The best option for verifying the computational methods is to use the results of cyclic tests of model disks. These tests make it possible to reproduce loading conditions and surface conditions that correspond to those of real disks, and the data on the load history and material properties make it possible to simulate stress-strain behavior of disks under test conditions by calculation. This paper shows the process of planning such tests. It is assumed that the tests will be carried out in two stages - before and after the initiation of a low-cycle fatigue crack. A number of criteria are formulated that the geometry of model disks and their loading conditions are to satisfy. Based on these criteria, model disks were designed and the conditions for their testing were selected.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2019;18(3):143-154
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Methods of validation of the ballistic structure of space surveillance system orbital segment
Fadin I.A., Yanov S.V., Samokhvalov O.A.
Abstract

Space activity brought about the space debris problem that constitutes a threat to active spacecraft. Nowadays the most efficient way of spacecraft protection against space debris is choosing the appropriate orbit parameters to prevent collisions of space objects. To do this one should know the parameters of motion of space objects (SO). At present the task of determining SO orbit parameters is solved be means of the space surveillance system (SSS). The Russian space surveillance system includes only ground based facilities located on the territory of the Russian Federation and Tajikistan. This fact does not allow determining the parameters of SO motion over the Western and Southern Hemispheres. The task of monitoring SO in low orbits (up to 2000 km height) is of particular importance because there have already been collisions that generated a lot of debris which, in their turn, pose a new threat to Russian active spacecraft. To prevent prospective threats to the Russian orbital constellation associated with possible generation of new debris as a result of impacts or spontaneous separation (because of an explosion, for instance) of active SOs the parameters of motion of newly emerging space objects need to be determined quickly and efficiently. We propose to solve the task of online monitoring of space object motion by creating an orbital segment of SSS. The creation of the new system is to be preceded by the development of scientific methods for justification of its ballistic structure. This article presents a method based on the solution of an optimization task, where the target function is the dependence of the required number of measurer spacecraft on the quality indicators of space surveillance.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2019;18(3):155-165
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MECHANICAL ENGINEERING
Determining the rheological properties of viscoelastic materials by the values of creep strain
Ivanov E.Y., Kirpichev V.A.
Abstract

Determination of creep strain arising due to stresses acting up to the moment of time t is considered. The phenomenon of constant-stress creep is described. A method is proposed to determine the parameters of the Arutyunyan creep kernel selected to describe the behavior of a material using two creep curves of a material with viscoelastic properties and nonlinear dependence of creep strain on the stress. In addition, the constant in the expression describing nonlinear dependence of creep strain on the stress is defined. The AMg6M alloy, widely used in the design of aerospace products, was chosen as the material to be analyzed. The tests were carried out on samples 3 mm thick at strains of 65 MPa and 156.9 MPa. According to the results of testing samples of materials on the test bench of Samara University creep curves were obtained. By determining the parameters of the approximation of the Arutyunyan kernel and the parameter included in the expression of nonlinear dependence of creep strain on the stress, it is possible to determine the value of the creep strain of the material for arbitrary values of stress and time. Comparison of the experimental and calculated creep curves for the AMg6M alloy confirms the validity of determination of the rheological characteristics of the tested material.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2019;18(3):166-172
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