Vol 13, No 5-2 (2014): Special Issue

Full Issue

Modification of the surface of silicon carbide parts by laser treatment for improving their tribological properties
Murzin S.P., Balyakin V.B., Zhuravel L.V.
Abstract

Laser microstructuring of the surface can be used for improving tribological properties of materials. This trend suggests a laser treatment to create on the material’s surface microstructures with spatial selectivity of physical-mechanical properties, such as microhardness, friction factor, etc. The microstructuring of the external surface of gas-dynamic compactions is perspective. To increase the capacity of the practical use of it is expedient to enhanced functionality through the use of laser microstructuring of the more common laser systems with pulse durations in the millisecond range. A method of surface’s modification of silicon carbide details by laser treatment for improving their tribological properties has been developed. A material structure in the heat-affected zone after laser microstructuring has been studied. Evaluated the morphological changes of the treated surface after a repetitively pulsed laser exposure. It was established that the pulse-periodic laser exposure leads to the formation on the polished surface of the silicon carbide parts recesses are round to oval. Along with the formation of acyclic microrelief occurs modifying surface structure details. Under laser exposure on the surface of the ceramic material is a decomposition of silicon carbide and graphite to form a solid solution of carbon in silicon. Supposed to carry out the study of the tribological properties of the resulting structures.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):9-16
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Rotary isochoric combustion chamber of a gas turbine engine
Porshnev V.A.
Abstract

In the article the combustion processes in isochoric rotating combustion chamber and the combustion products expansion in the turbine and the nozzle are considered, the main theoretical calculations are provided. The peculiarity of the combustion chamber design of the gas turbine engine is that it is formed by a rotary disk composed of a boss and blades, oriented along the axis of rotation, joined at the ends by the shell and the input and output disks with slots. The slots on the input disk are designed to fill the combustion chamber with the fuel air charge. The slots on the output disk are designed for the output of combustion products and feeding them on the turbine blades. The process of combustion of the fuel-air mixture occurs when the blade-to-blade space of the combustion chamber is closed by the input and output disks. The combustion occurs in a confined space, i.e. the condition of the isochoric process is fulfilled. It is shown that the gas emerging from the chamber after combustion at υ=соnst, is expanded in the turbine and doing work. The available turbine work in a gas turbine engine depends on the nature of the combustion chamber filling and, consequently, on the cycle implemented in the plant. The actual work of the turbine is determined by the value of its efficiency, which, in turn, depends on the nature of the expansion process. The research carried out has allowed to conclude that the use of gas turbine plants with the cycle υ=соnst can increase the thermal efficiency by 20%. This concerns, first of all, gas turbine engines with a small degree of pressure rise and is expressed in increased power and efficiency without changing the mass of the engine. In addition, the use of cycle υ=соnst in conventional gas turbine engines at maximum operation does not require significant design changes.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):17-21
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Multicriterial choice of the best variant of the pulse detonation engine design for aircraft angular stabilization and orientation systems
Safronov V.V., Porshnev V.A., Zhebrakov A.S.
Abstract

The verbal and mathematical formulations of the problem of multicriterion ranging of the pulse detonation  engine design variants were carried out. Using the method of morphological box the morphological table was composed, on the basis of which many possible design variants of the pulse detonation engines were generated. When compiling the morphological table a conception of pulse detonation engines in the form of the following subsystems was considered: detonation chamber, components supply system, initiation system, control system. Eventually as valid options, which were subjected to a study on the firing test bench, we selected twenty variants. The system of criteria for the assessment of the pulse detonation engines design variants (specific thrust, frontal thrust, specific consumption, unit weight, length) was proposed. Criteria values were determined during firing tests. The peculiarities of solving problems by using the methods of "hard" ranging, hierarchies analysis, Borda`s method were discovered. The criterion formation of the true Pareto tuples was formulated. Using the methods of "hard" ranging, hierarchies analysis, Borda`s method, the criterion of the true Pareto tuples formation the applied problems of choosing the best pulse detonation engine variant for three important cases were resolved: - the atmosphere is taken into account, pulse detonation engine suffers the influence of the frontal resistance; - the atmosphere is taken into account, pulse detonation engine is located inside the aircraft and does not suffer the immediate impact of the frontal resistance; - the influence of the atmosphere is not taken into account, only pulse detonation engines without ejector are subject to the analysis. The best pulse detonation engine design variants for different values of the criteria priorities were revealed.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):22-34
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Development of a prototype of a multi-loop closedbrayton cycle gas turbine power system
Arbekov A.N., Novitskiy B.B.
Abstract

Aim is to develop the prototype of a multi-loop closed-Brayton Cycle gas turbine power system, which allows to simulate the cosmic power plant capacity from tens to hundreds of kW intended for food or electrorocket thermal engines with electric heating, as well as the powerful energy systems of spacecraft for various purposes. Creating a prototype model allows to study the joint operation of two gas-turbine power converters in a single circuit of the total gas heater (which acts as an electric heater), build a control algorithm modules in transitional processes, investigate the processes of starting and stopping of the modules, as well as select the optimal control algorithm starting and to identify the fundamental problems in the design and construction of the installation in the early stages of development of space multiloop systems. The paper contains estimates of the main parameters of a closed gas turbine plant and the optimization cycle to allow the use of existing sites. Also presented an algorithm for calculating. Based on the data as the working fluid was chosen gelieksenonovaya mixture with a molar mass of 83.9 kg/kmol, which is an analogue of the thermodynamic krypton. The parameters of a multi-loop closed gas turbine plant and layout version of the two-loop closed-Brayton Cycle gas turbine power system.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):35-41
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Experimental investigation of a small-sized centrifugal compressor for a closed-brayton cycle gas turbine power system
Arbekov A.N., Novitskiy B.B.
Abstract

An experimental characterization of small-size centrifugal compressor for turbine-driven generator-compressor unit of a closed-Brayton Cycle gas turbine power plant is presented. Operating fluid is a mixture of inert gases. Bench equipment (replacement of pressure sensors and systems for collecting and processing signals) was upgraded for characterization to complete control of research. The paper describes the test facility, the equipment used and the method of research performance. Test runs were carried out in air compressor, with a cover of the throttle before the surge. Comparison with the calculated point restated at the speed of the experiments (30 000 rev / min) is presented. The influence of the physical properties of the working fluid on the performance of a centrifugal compressor at the calculated pressure ratio (1.75) is evaluated. Experimental research on Xenon and helium mixture (molar mass of argon) and argon at full throttle and varying speeds from 23700 to 30300 rpm is presented.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):42-47
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Automated thermovacuum firing test facility for testing and research of workflow in low-thrust rocket engine on hypergolic propellants
Galperin R.N., Ivashin Y.S., Nigodjuk V.E., Ryzhkov V.V., Sulinov A.V.
Abstract

The paper presents a description and the technical characteristics of newly created and upgraded systems of automated thermovacuum fire stand for testing and research of the workflow of liquid rocket thrusters (small thrust jet engines) working on hypergolic propellant components. The stand allows to determine the energy and dynamic characteristics of small thrust jet engine with thrust from 0.1 to 100 N in the continuous and pulsed operating modes; to explore the intrachamber workflows; to study kinetic properties of gasified liquid intermediates of liquid-phase interaction of hypergolic propellants; to explore the thermal state of the engine under high altitude conditions; to provide research of the power, heat and polluting impacts of small thrust jet engine jet on elements of structure surface of the spacecraft; to explore of diagnostic methods of the small thrust jet engine functioning and others. Automated measuring and information system of the stand provides small thrust jet engine management on a given cyclogram; carrying out the calibration of channels for measurement of parameters of small thrust jet engine: thrust, flow rate of components, pressure, temperature, etc.; collecting information from the measuring channels of the stand during tests and information storage on the hard disk; processing of measurement results on the computer during the test and their representation in the required form (protocols, characteristics, charts and tables); formation of database of engines studied. For measuring the temperature of the outer surface of the chamber of small thrust jet engine is used contactless method using an infrared thermal imaging system. Complex work for improvement of element base and systems of automated thermovacuum fire stand for testing and research of workflow of small thrust jet engine working on hypergolic fuel components was expanded the opportunities of stand in the field of new tasks statement for workflow working off and increase the accuracy of the main parameters measurement for the engines.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):48-58
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Investigation of transformation of intermediate products of liquid-phase interaction propellant at the onset of combustion for rocket engine
Nigodjuk V.E., Sulinov A.V.
Abstract

The results of an experimental study of the conversion of intermediate (liquid-phase and gasified) product exothermic liquid-phase interaction of hypergolic propellant components in the initial stage of combustion are presented. To investigate the present step conversion of intermediates experimental method for the flow reactor is used. In the process of the experiment the centrifugal and wedge mixing elements is used as propellants mixing systems for flowing reactor. This mixing elements allowed interaction of components in the liquid phase and subsequent flow of the liquid-phase intermediates on the wall of the reactor. Thereby dividing the flow of liquid and gasified intermediates in cross-section is achieved. During the experiment the effect of the following basic parameters of the processes of transformation of intermediates is revealed: the effectiveness of liquid-phase mixing of the fuel components, the residence time of intermediate products in the channel and the pressure of gasified products. Results of the study of converting liquid-phase intermediates in the combustion stage confirm the assumption about the prospects of using of liquid-phase products for internal cooling of rocket engine chamber wall provided efficient organization of the chamber working process, because of the temperature of liquid-phase products, washing the inner surface of the channel changes slightly along the entire length of the channel. Exothermic processes of liquid-phase interaction between fuel components at this stage is substantially complete. Heat removal of energy from previously gasified intermediates is required for subsequent gasification of liquidphase intermediates. Unlike the liquid-phase conversion of intermediates, converting process of the gasified intermediates occurs quite rapidly in the initial stage of combustion. The temperature of gasified intermediates depending on the boundary conditions in preflame zone was ~ 900 ... 1100 K, and in the output section of the channel of the reactor reached ~ 1400 ... 2000 K.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):59-66
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Determination of the conditions of nanoporous structures formation in metal materials by pulse-periodic laser treatment
Murzin S.P.
Abstract

The influence of the laser treatment to create a nanoporous structure in copper-zinc alloy has been searched. Laser treatment of pulse-periodic radiation enables to form a stable stress state on the sample surface at a temperature that does not exceed the melting point. The conditions of nano-pores formation mainly of the channel-type with the depth of the area of nanoporous structure formation not less than 40-45 μm has been ascertained. The re-searches of the surface layer structure of the copper-zinc alloy L62 after laser treatment have shown that in the cross-section the pores are oriented from the surface to the deep of metal and the pores concentration is decreasing with an increase of distance from the surface. The laser treatment creates a nanoporous structure in the surface layer. Temperature and speed modes of treatment which mainly cause the channel-type nanopores formation with a width ~100 nm, which form a nanoporous network, are determined. Likewise the vibration speed measurements of the samples were carried out. Regardless of the external laser exposure frequency the maximum values of the vibration speed occur at almost the same frequencies corresponding to the natural oscillation frequencies, under such conditions the nanoporous structures are formed. Damping device application significantly reduces the vibration speed values. In this case, the formation of the nanopores in the metal material does not occur.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):67-74
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Designing of low-flow rate slider bearings for turbomachinery rotors
Parovay E.F.
Abstract

In this paper, constructions’ peculiarities and an action mechanism are described as well as a design process of low demand sliding bearings. The analysis of the existing design methodologies shows their imperfections and impossibility adequately applying for characterization of low-flow sliding bearings. These bearings is operated under low lubrication supply (no oil bath). Efficiency of the proposed design of the sliding bearing is based on availability of the elastic suspension, bushings' bore in the radius of the shaft, which minimizes the time of boundary friction and increases the bearing life. Described hydrodynamic model of the working gap allows to determine the characteristics of the oil-flow. As a result of computational research has been established a generalized designing method for new type of bearing, comprising stages: geometry choice, 3D-design, finite element models of the narrow gaps creation, the calculation of the oil-flow characteristics, calculating the characteristics of the elastic suspension, polycriterial optimization. Also shows the results of computational research of bearing's characteristics (diagram of pressure, depending the characteristics of the flow of lubricant on the angle of bushings, etc.). Recommendations are given for optimizing the design and choice of materials.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):75-81
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The influence of maximum temperature of heating on the thermal fatigue of nickel heat-resistant alloys under thermocyclic tests
Tikhomirova E.A., Sidokhin E.F.
Abstract

The analysis of high temperature resistance alloys thermocyclic tests show that the lifetime Np is less when maximum temperature Тmax in test cycles (ΔТ=Тmax-Тmin) is more 900°С. In most test cases thermal cycle contents the plastic deformation. The cooling half-cycle includes three temperature intervals: first – where heating halfcycle compression stress decrease take place, second – where tension stresses are increased to yield stress σ02 and plastic deformation begin, and third interval - plastic deformation region, which is finished at minimum temperature of cycle Тmin. The stress decrease interval length depends from value of stress, which is reached in precede heating half-cycle and, as we consider, equal σ 02(Tmax). High temperature resistance alloys are characterized by yield stress σ 02 sharp decrease at temperatures which is more 900°С. Because at cooling from temperatures, which is lower 900°С, stresses, which must to decrease, are larger on one third them at 1000°С and on half them at 1100°С. Therefore third temperature interval is shorter at cooling from temperature which is more 900°С, plastic deformation is more and lifetime NP smaller.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):82-87
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Ways of improving burners of two-staged combustion chambers
Bantikov D.Y., Grechishnikov O.V., Rogalev V.V., Roslyakov A.D., Tsybizov Y.I.
Abstract

This article contains materials about defect of two-stage combustion chamber gas turbine engine occurring by high temperatures. The design of basic burner with blade swirler is shown. Improvement of burner by using of the minimum of design changes is required. Ways by absence overheating of elements homogeneous burners combustion chambers is developed. Six variants of burners were selected for their studying. They were made by machining bush of basic burner. This machining bush consists of increasing diameter of inner center hole. It is having variant complete deleting bush and his changing on groove nozzle. Data of experimental works to determine capacity eight types of burners as function of air pressure and formatting field of pressure on edge of burner is presented. The research result of two types burner with groove nozzle for search new ways to solve task of increasing reliability burners is shown. Optimal method tweaking burners for absence overheating swirler was selected.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):88-94
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Research of gas turbine engine operation in dust-filled atmosphere
Abdullin B.R., Akmaletdinov R.G., Goumerov K.S., Nigmatullin R.R.
Abstract

The article describes the experimental data on the effect of erosion the turbomachines elements under the influence solids on the engine performance. The analysis was performed for the generator of compressed air for the aggregate of cleaning pipelines and the gas jet treatment plants temporary technological railways. The aggregate of cleaning pipelines was operated under conditions of high concentrations of dust in the air - in the semidesert. Both plants are based on the converted aircraft twin-shaft turbojet engines. According to the model of erosive wear was set, that the depth of erosion depends on the dimension of the engines. Also shown is the ability to detect impending failure of the engine working in a dusty atmosphere, based on trend analysis of its parameters using various statistical smoothing options: simple linear trend, exponential trend, damped trend. Revealed that the first of the considered parameters controlled workflow approach to engine failure reacts high pressure rotor speed. Timely detection of trends in parameters due to the development of a number of irreversible processes will predict current and stable operation of the critical state of gas turbine engines, the corresponding loss of gasdynamic stability of the engine, so as to use the work on modes near with the marginal stability of the compressor is unacceptable.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):95-102
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Nonsynchronous vibrations of turbomachinery bladed discs
Basov P.A., Seleznev V.G.
Abstract

The paper brings forward the method of determining nonsynchronous vibrations of turbomachinery bladed discs, based on the hypothesis of mechanical generator. Turbomachinery stages represented as a mechanical generator open up new opportunities for test results interpretation for the purpose of gas-turbine engine mounts development and make it possible to improve the reliability of diagnostics of nonsynchronous vibrations and their occurrence and development mechanism. Turbomachinery bladed discs represented as a mechanical generator component part revealed that nonsynchronous vibrations of turbomachinery bladed disc are determined by design features of bladed disc and vane. The paper contains some examples of spectra for fan strain-gauging results, on the basis of which the analysis of nonsynchronous vibrations of turbomachinery bladed discs was carried out. Vibrations of bladed disc with forward and backward strain waves having coefficients k1 and k2, respectively, are considered as a mode of bladed disc being a part of the mechanical generator, which vibration mode is presented by the algebraic sum of broken coefficients. The algebraic sum of these coefficients equals with a ratio of vibration frequency of bladed disc as a mechanical generator part to rotation frequency. The introduced generator of mechanical vibrations model can be applied to the analysis of nonsynchronous vibrations when processing results of turbomachinery bladed discs rig tests.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):103-108
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The study of shrouded fan vibration modes and frequencies on holograph and as a part of the engine on the test rig
Koskin A.O., Seleznev V.G.
Abstract

The article reports about application results of holographic interferometry method for the analysis of rotating fan vibration modes. So far there are no practically the experimental works explaining behavior of turbomachinery bladed discs as a part of the engine, on the basis of knowledge about modes and frequencies of observable disc in the absence of rotation. Having initially bladed disc amplitude-frequency characteristics in the form of vibration modes pictures with the corresponding frequencies, and then strain-gauging data for this disk being a part of the engine, makes it possible to carry out the vibration modes analysis of rotating disk. Vibration modes, received on holographic installation, are identified with vibration modes of a rotating disc on coincidence of their frequencies.Vibration frequencies and modes of a fan first stage, received on holograph, and the frequencies, received using spectral analysis method for strain-gauging data, are given in the article. Close values of these frequencies allowed to connect vibration modes with rotating disc frequencies. Moreover, there is the example of turbine rotor disc research, illustrated the importance of knowledge of turbomachinery discs vibration modes, in the article. The study revealed the existence of "horizontal" connection for some vibration modes, when two different vibration modes accord with almost the same frequency. On the basis of the carriedout study it is possible to draw a conclusion that before installation of the bladed disc in the engine it is necessary to define natural frequencies and vibration modes of this disc using modern optical methods, in particular a holographic interferometry; that will allow to predict more reliably any occurrence of disc vibrations during its working as a part of the engine.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):109-114
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Experimental research of heat exchange in a plane channel using the regular thermal regime mrthod with different Biot numbers
Kolesova E.G., Veretennikov S.V., Zhornik M.N.
Abstract

The results of the experimental study of heat exchange in flat channel, executed by method lazer stereolithography, is presented. The studied heatexchange surface represents the thin metal plate forming one of channel sidewalls. Researches were performed under different criterion Bi in broad range criterion Re. For determination of heat-transfer coefficient is used infrared heat diagnostics, in base which prescribed method of the regular heat mode of the first sort. At first the metal plate was heated, after through an internal channel turned on blowing cold air. Temperature of plate was measured by infrared thermography. In processing the results were based on graphics logarithm excess temperature from time. Slope ratio of the curves is the rate of cooling of the plate. The borders of application of this method are experimentally determined from criterion Bi. The experimental results coincide well with the known criterion dependence Nu=0,018Re0,8. Developed experimental setup and methodology of transitional experiment allow to determine the heat transfer coefficient in forced for restricted flow, when the regular warm mode of 1 type is realized.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):115-120
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Perfection of methods of conducting resonance tests of rotor blades being part of the engine
Khorikov A.A., Danilkin S.Y., Redkin D.A.
Abstract

The new method of resonance test of rotor blades using blade oscillation non-contact diagnostics is presented. Diagnosticsis based on narrowband spectral analysis of signals with high static pressure pulsation sensors mounted on the engine case. Experimental results of the turbomachinery rotor blades dynamic strength at bench tests using non-contact diagnostics resonance vibrations of blades are given. It is studied the resonant vibrations of rotor blades of the compressor and turbine of experimental turboprop engine and high-pressure compressor of a gas turbine engine with a promising diagnostic method using resonant vibrations of rotor blades by the signals from the sensors pulsation of static pressure, based on the measurement of pressure fluctuations in the flow of the blades repetition frequency, with using the Campbell diagram, identified by waveform blades, the main harmonic excitation of resonant oscillations of circumferential unevenness flow, as well as modes for the resonance testing of rotor blades. It is shown that the application of the new method can significantly improve the efficiency and reliability of the rotor blades resonant vibrations diagnostics, and reduce material costs of resonance testing compared with traditional technology determine the resonant modes on the basis of the calculation methods.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):121-127
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Development of a mathematical model of winding made of non-impregnated aramid fibers for strength analysis of the combined fan case in GTE compressor blade separation
Krundaeva A.N., Shmotin Y.N., Tomilina T.V.
Abstract

The design of a combined case with wound non-impregnation aramid fibers is presented. The main purpose of winding non-impregnation aramid fibers is to prevent the departure of the blade beyond the design of the engine. Wound non-impregnation aramid fibers - a new trend in security systems for aircraft gas turbine engines. Such systems are very cost-effective (value for money) to solve, for example, the problem of localization of the fragments of the engine when the blade is broken, since the threads have high specific strength per unit of weight. In this regard, the introduction of engine design combined body is a very promising solution. The principle of operation of a combined case is as follows: compressor blade breaks into contact with the adjacent blades and the housing. Metal case partially destroyed. Fragment blade engages through a metal casing with a thread wound to absorb the main part of the impact energy and keep the blade fragment to the drawing and friction with each other. For the proposed options to protect the body from Flight of the blade turbine engine developed a mathematical model based on the design of the complex LS-DYNA. The created model is verified by the results of field experiments and used to calculate the retention case cut short blades of a gas turbine engine.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):128-134
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Results of numerical modeling of two-phase liquid / gas flow on the basis of a simplifield model of oil chamber
Lisitcin A.N., Badernikov A.V., Pechenik E.V.
Abstract

Numerical simulation results of multiphase liquid/gas flow are presented. Calculation was preformed for simplified bearing chamber. Work was kept within the framework of developing the methods of multiphase flows modeling in oil chambers of gas-turbine engine. At present there is no the instrument of the analysis, allowing to simulate the oil flow in oil systems, and oil chambers of gas-turbine engine. The tightening requirements to mass, overall dimensions and performance of the engine need to reduce of the oil system sizes and amount of the oil, used for lubrication and cooling of bearing with increasing of their resource. At present, oil chamber design based on successful previous experience of the similar work, but performance of oil system is checked only in process of the engine test. This problems in this case lead to significant time and financial expense, so this instrument of analysis allow simultaneously increase the bearing resource, reduce mass and size of the oil system. The most rational model of multiphase flow was also chosen and analysis of the mesh size influence on steady calculation results was made.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):135-142
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Combined treatment technology for slot channels of cooling systems
Rodionov A.O., Suhochev G.A., Kodentsev S.N., Smolyannikova E.G.
Abstract

The article presents the results of the searching and experimental research in the field of treatment of discontinuous surfaces in parts of cooling systems. The existing methods and means of technological equipment for providing of quality surface treatment of slot channels are described. Slot channels are especially technologically complex for treatment. A new method of combined treatment was proposed based on an analysis of existing treatment methods. The method allows to achieve the specified operational characteristics of .slot channels. Basic technological principles to design a new method of finishing of small-flow parts, which combines finishing and control operations, are developed. In article the mechanism of combined finishing for slotted channels are described. The results of experimental verification of the technological capabilities of the combined treatment are presented.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):143-149
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Development of methods of modeling and computer-aided design of compressors
Krivosheev I.A., Rozhkov K.E.
Abstract

Discusses the methods of calculation allowing to calculate the characteristics of cascades of profiles, rows blade, the compressor as a whole. Make improvements to previously known methods of calculation. It is proposed to allocate an additional (along the surface current) elementary channels that can achieve output of rows diagrams parameters. Preparation thus permits the compressor, in turn, to calculate the characteristic of the developed engine steady and unsteady modes with high accuracy. The proposed method allows the selection of geometric parameters of blade rows, and in operation - perform account the influence on the characteristics of changes in the geometry of the blades (due to erosion, dirt, etc.). Allows you to analyze the effect of prepollution and erosion of the blades to change the characteristics of the nodes, and the results of the identification of the plant model to solve the inverse problem - to identify the actual values of pollution and erosion in specific stages and crowns. The resulting geometry of the rims may be used as an initial approximation for the boundary conditions at the solid-state 3D modeling and gas-dynamic calculations in СAE- systems such as Ansys CFX.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):150-158
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Investigation of 11D428А-22 thruster operation dynamics with bellows flow stabilizer
Beshenev Y.A., Volkov A.V., Kazankin F.A.
Abstract

This paper presents the results of comparative fire test investigations of the bipropellant thruster 11Д428А-22 with both plate and bellows flow stabilizers. The direct-acting bellows flow stabilizer 11Д428А.410.00/-01 presented in this paper meets all current requirements and progress trends of such type of hardware. In the developed stabilizer the bellows is used as a sensitive element, which excludes any uncontrollable leakages of a working medium and improves the reliability by eliminating cramping and varying frictional forces typical for pistons and plungers. The use of bellows-expanding spring at an initial state of the stabilizer extends the regulation range of the latter and increases the maintenance accuracy of specified flow over the entire control range. The flow stabilizer provides the starting propellant flow at the expense of added mass; hence the negative regulator effect becomes the favorable one in respect of a feed pipeline of liquid propellant thruster to improve thruster operation dynamics. Novelty of the flow stabilizer configuration is combining functions of a regulator and a starting device and broadening a regulation range and accuracy due to the spring expands the bellows at the initial state. The development construction is easy to fabricate and it provides the agreement of calculated regulator parameters and those resulted at the tests.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):159-165
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Development techniques of casting complex parts of aerospace profiles using additive technologies
Agapovichev A.V., Balaykin A.V., Smelov V.G.
Abstract

The use of rapid prototyping technologies to create new industrial products, with particular importance is the cost and speed of production, is a unique opportunity to use cost-effective methods for the production of parts by investment casting. At the stage of pilot production, which is characterized by frequent changes in design, the problem of the rapid production of cast components becomes crucial. This is mainly due to the complexity and the complexity of manufacturing foundry equipment. In turn, the research and development of rapid prototyping technologies have allowed a new level of optimization and the introduction of new technologies in the investment casting. The aim of this work is to identify opportunities and evaluate accuracy of the size of the casting during investment casting using rapid prototyping technology. The work was conducted with the use of cross-cutting design in CAM / CAD / CAE systems. The study size and precision parameters of the casting was conducted in co-ordinate measuring machine. The work has been verified the adequacy of the virtual simulation of the process of forming a casting in the casting simulation ProCAST, in comparison with those obtained castings. The study showed that the use of rapid prototyping technologies with investment casting can significantly reduce the time for making castings, reduce production costs and improve the accuracy of the size of the casting.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):166-172
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Development of a single-section demonstrator rotary engine on the basis of a modern complex design procedure
Kostyuchenkov A.N., Zelentsov A.A., Semenov P.V., Minin V.P.
Abstract

There is no manufacture of aviation engines in power range of 100-300 hp. One of the most perspective decisions of the domestic low-sized aviation engines developing is creation of engines on the basis of modularity principle. This principle consists in designing of the unified power part and creation on the basis of it multisection or multicylinder engines for maintenance necessary performance. Most simply given problem dares at creation of rotary engines. The paper presents modern design procedure of single rotary engine. This procedure includes statement of target engineering performance, calculation of the basic dimensions of rotary engine, engine performance assessment subject to gas dynamics and mechanical losses, simulation of working process subject to basic dimensions of rotary engine and heat transfer into combustion chamber wall. 3D-model of rotary engines is created on the basis of calculations mentioned above. Calculation of engine geometry is carried out by analytical methods. Performance of rotary engine is calculated by using modern software. The 100 hp single rotary engine project was developed on the basis of this design procedure. In future this design procedure will be applied for developing 200 hp and 300 hp aviation rotary engines.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):173-181
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Influence of tension and contact stress on sliding in cylindrical roller bearings in support of gas turbine engines
Belomytcev O.M., Pischalnikov A.B.
Abstract

The tie between coefficient of slip and tight in a roller bearing 1032930 rotors of the turbine jet of PS-90 family with a rated mounting gap of 0,0425 mm is established. Tight in the bearing is defined in the estimated way depending on thermal deformations and inertial forces. Values of temperatures are taken from bench tests of the engine in case of rotational speeds from 9228 to 11308 RPM, the values of tight corresponding to them depend also on fit of an outside ring with the casing (the damping sleeve). In case of fit with tight in the bearing tight makes from 0,021 to 0,058 mm, in case of fit with a gap – from-0,0059 to 0,0478 mm. Owing to volume compressive stress of a shaft and stretching of the casing with a bearing outer ring of value of contact deformations and stress from tight considerably decrease, expressions for determination of each type of deformations are given. Stress of contact deformations is determined by a formula of Hertz and can change from 0 to 901 N/mm2 depending on rotational speed and fit of an outside ring with the casing. Curve dependences of values of tight, temperature, contact stress and coefficient of slip from rotational speed are constructed, so in case of tight from 0,0464 to 0,0558 mm and stress from tight of 659-895 N/mm2 the coefficient of slip makes about 2%. The valid stress in contact is unknown as conjugation of an outside ring to the casing has indefinite character, in case of the combined support the dispersion on deformation of a ring significantly will decrease that will lead to smaller dispersion on such indexes as coefficient of slip and longevity of the bearing.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):182-188
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Problems of ultralow power turbine design in a turbine drive system
Kalabuhov D.S., Grigoryev V.A., Rad’ko V.M.
Abstract

Ultralow power turbine drives (ULPTD) are used in the aerospace industry and in other sectors of the economy as source of energy for ancillary systems. At present, the actual task is improvement of their efficiency. One of the most promising areas for its increase is to optimize the parameters of turbine drive already in the early stages of design.The article discusses the design of optimalultralow power turbine (ULPT), which is the main hub of ultralow power turbine drive. The basic problems of ultralow power turbine drive system optimization through a systemic approach to design. The problem of optimization is tasked as a problem of the conventional vector structural-parametric optimization. Methods and algorithms for its solution, justified criteria for ULPTD effectiveness evaluating, selected optimized parameters of axial and centrifugal turbines types are described. As the performance criteria is selected coefficient of performance (COP) of the turbine, its mass, the specific consumption of the working fluid, the cost of operating turbine drive. Expediency calculation mode selection in the optimization process of regime parameters evaluation criteria for generalized on ULPTD modes efficiency is grounded. Results on the effect of uncertainty on the value of project information criteria are given.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):189-200
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Peculiarities of laser welding of thin parts of aerospace equipment
Smelov V.G., Sotov A.V., L’vov M.V.
Abstract

In this paper, the laser welding methodology technological process optimization of shallow thickness aerospace constructions was considered. The methodology consists in selecting of multivariate iterative process parameters. Using this methodology can significantly reduce the technological preparation time of production and the proportion of experimental research. Experimental confirmation was work on laser butt welding parts for shallow thicknesses, material welded samples - nickel-based alloys. Work was carried out to determine the chemical composition of the alloy samples, modeling and development of a special device for welding products. Laser welding is carried out on the process plant includes a pulsed solid-state laser YAG:Nd with a wavelength of 1,06 microns. On the basis of the developed method of optimization parameters were selected welding process. According to the results of work defines the quality of the welded joint specimens using metallographic examination of the weld, and testing of mechanical properties of butt weld specimens were performed, the tensile strength was determined. The developed method of process optimization of laser welding of parts of small thickness allows for high quality welds free of defects in the surface layer.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):201-206
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Formation of a method of choosing rational values of ultralow power turbine parameters in a turbine drive system
Kalabuhov D.S., Grigoryev V.A., Rad’ko V.M.
Abstract

The problem of structural and parametric optimization of ultralow power turbine (ULPT) in the system of turbine drive (ULPTD) on the initial design stage is formulated. It is described a method and algorithm for selection of rational value sand schemes of ULPT during optimization. Optimization problem involves the use of par ametric minimax principle of optimality in the choice of a rational variant of the turbine, which ensures the reliability of selected solutions. The estimation of the reliability and method effectiveness developed by its validation with the method of designing multimode ULPTD аnd results of computational experiments. The examples of energy and mass efficiency improving of aerospace turbine drive special purpose using the developed method are given. Validation was carried out by the example of the initial design of multi-mode centripetal turbine drive for special purposes. It has been shown that the efficiency by mass turbine drive special purpose can be enhanced with minimal loss in efficiency, if the two-criteria optimization problem solving. Its decision at a loss in terms of efficiency and weight of 1.8% and 11% with respect to the results of a one-criterion optimization possible to increase the efficiency of turbine drive initial version by 6.5% and reduce its weight by 25%. Also it is formed a look of turbine drive switching device. The use of axial turbine instead of centripetal at worst case of original data has allowed to reduce the specific consumption of working fluid and the specific drive mass on the 24 and 48%, respectively.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-2):207-216
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