Vol 13, No 5-4 (2014): Special Issue

Full Issue

Formation of spread in resonance stresses in bladed disks with non-identical blades and loose vibration conectedness
Ermakov A.I., Urlapkin A.V., Fedorchenko D.G.
Abstract

The paper discusses the forced vibrations of mistunedbladed disks and loose vibration connectedness on the example of the model disk. It is shown that such wheels in separate frequency bands are losing the main features characteristic of systems with a small deviation from rotational symmetry. This leads to a qualitative change in the nature of their oscillations about the exciting harmonics. Otherwise becomes a mechanism for the formation of these scatter resonant stresses. It is found that the resulting vibrations in the bladed disks with a mistuning and loose vibration connectedness are a superposition of vibrations in several successively excited forms one family, the number of which may be up to a number of limited order of symmetry of the system occurring in the frequency range, depending on the accuracy of the blades.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):9-13
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Optimization of the design of a railway searchlight in the ANSYS software environment
Abulkhanov S.R.
Abstract

In article results of determination of eigenfrequencies of a design of a searchlight of an electric locomotive of the VL series by means of program system of the final and element analysis of ANSYS are stated. The solid-state model of a searchlight having physics and technology parameters of components of a design and the geometrical sizes of a real searchlight was developed for the analysis of vibrostability of a design. As a light source of a front lamp the incandescent lamp and light-emitting diodes were used. Thus for a light-emitting diode the boss from the ceramic material preventing thermal deformations of a substrate was designed. The quantity of light-emitting diodes was chosen, proceeding from lighting requirements to illuminants on the Russian railroad. The analysis of solid-state models of the searchlight using as a light source the incandescent lamp and light-emitting diodes, showed that the searchlight design with light-emitting diodes has weight on 900 grams bigger than a searchlight with the incandescent lamp. The received sizes of eigenfrequencies were compared with frequencies of periodic vibrations which are tested by the rolling stock. For frequencies of vibrations, possible on railway locomotives, deformations of two designs of a searchlight which showed were defined that shortcomings are inherent in both designs. When using as an incandescent lamp light source eigenfrequencies of a design promote destruction of a flask of a lamp, both on top, and at low frequencies of the fluctuations inherent in a range of vibrations of the locomotive. In case of use of light-emitting diodes in a searchlight nature of deformations of a design indicates the need of reduction of its component weight at preservation of necessary rigidity. The carried-out analysis allowed to reveal the directions of development of a design of the searchlight, vibrostability of a searchlight providing increase with a LED light source: application of edges of rigidity and facilitating grooves.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):14-20
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11D58MF combined propulsion unit operating on oxygen-hydrogen fuel for an average-sized booster
Lupyak D.S., Smolentsev A.A., Sokolov B.A., Tumanin E.N., Tupitsin N.N.
Abstract

This paper describes the expediency of creation a combined propulsion unit with oxygen-hydrocarbon fuel for advanced upper stage of the middle class rockets based on the multifunctional liquid-propellant rocket engine 11D58MF. The appearance of the upper stage with 11D58MF engine, comparative analysis of the developing and exploitation upper stages are presented. The peculiarities of 11D58MF engine notes. At present there is a number of objective reasons and circumstances in which it is necessary to carry out works on the creation of propulsion with oxygen-hydrocarbon fuel in the domestic space industry. This propulsion can be used as in creation of advanced upper stage for the space launch complex with family of the middle class launch vehicles "Souz" in launch site "Vostochniy" as in creation of upper stages for the light and ultra light class launch vehi cles. At that upper stage with new propulsion will be able to compete with the blocks that are being in developing or exploitation at present.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):21-28
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Assessing the influence of surface hardening on the endurance limit of specimens made of steel 40X using residual stresses of reference specimen
Sazanov V.P., Vakulyuk V.S., Shadrin V.K., Surgutanov N.A., Shlyapnikov P.A.
Abstract

The possibility of the employment of reference specimens hardened simultaneously with the parts has been examined for the hydroblasting influence estimation on the parts with concentrators endurance limit on the example of hollow cylindrical parts made of steel 40 with circular cuts of semicircular profile with the radius 0,3 mm. The investigation has shown that the difference between residual stresses values found by calculating and experimental methods doesn’t exceed 8% in smooth specimens, in specimens with cuts – 6%. Under the hydroblasting influence on the endurance limit estimation in conditions of bending in the case of symmetric cycle for hollow cylindrical specimens made of steel 40Х with cut of radius 0,3 mm it’s been established that the employment of residual stresses distribution calculated by the initial deformations of reference specimen let predict the specimens endurance limit increase under stress concentration conditions to an approximation of 8%. It has been shown that it’s reasonable to use the average integral residual stresses criterion calculated through the dangerous section surface layer thickness equal the non-propagating fatigue crack critical depth for the prediction of the endurance limit increase of hardened by hydroblasting specimens made of steel 40 with stress concentrators.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):29-36
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Influence of argon, propane and ethane viscous dissipation on the thermal state of a porous plate
Baygaliev B.E., Tumakov A.G., Tumakov E.A., Ibragimov A.I.
Abstract

The report provides information of using a differential equation of the temperature field of the porous plate, derived taking into account the heating of the skeleton due to the forces of friction when pushing the coolant through the porous plate. Temperature field of the porous plate is determined for different values of porosity and different types of coolant under the boundary conditions of the third kind. Calculation of the temperature field of the porous plate, taking into account the dissipation implemented through programs compiled in Matlab. When the porosity of the insert 0,20 viscous dissipation effect is present, but negligible. Increasing porosity does not lead to significantly different calculation of the temperature condition of the porous insert with and without consideration of viscous dissipation. So keeping the viscous dissipation per thermal state of the porous insert with a porosity of more than 0.2 is not washed away. It was found that the porosity of the matrix is observed increase its temperature. Results showed that when the water flow to the final boundary of the matrix, we can observe both an increase and a decrease in temperature, which indicates the importance of taking account of viscous dissipation and proper selection of both costs and porosities, and the kind of coolant.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):37-40
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Peculiarities of applying Darcy’s law in research and development of hybrid engine blades for an advanced aerospace plane
Baigaliev B.E., Tumakov A.G., Tumakov E.A.
Abstract

This work is devoted to the two methods of modeling porous material. Flow characteristics and, accordingly, the viscous and inertial coefficients for the models of porous materials consisting of spherical particles were obtained by calculation. On the basis of these data conformity assessment of flow characteristics for models of porous materials consisting of spherical particles of arbitrary filling and exactly the same on the geometrical dimensions of the flow model in accordance with Darcy's law was carried out. The data thus obtained were then used to estimate the energy dissipation due to viscous friction in the flow of fluid through the porous body. As a result reached the following conclusions. Firstly, in the absence of information about the viscous and inertial factors that determine the performance curve, data rates with sufficient accuracy can be obtained by calculation in the medium Ansys CFX for periodic fragment of the porous body. Secondly, there is a satisfactory agreement between flow performance for porosity γ≥0,1601 obtained in the medium Ansys CFX for periodic fragments of porous bodies and flow model in accordance with Darcy's law.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):41-50
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Creation of a data retrieval system for choosing the optimal cutting tool in manufacturing aircraft engine parts
Shulepov A.P., Meshcheryakov A.V., Ramzaeva E.A.
Abstract

The article presents the algorithm of a tool selection for edge machining cutting based on a number of principle criteries on selection of a cutting blade shape, tool-mounting system, tool material. The work gives a description of interface and database structure of information storage and retrieval system dealing with the selection of cutting tool and cutting mode in manufacturing of aircraft engine parts. There are a number of basic criterions that have an impact on the selection of the cutting plate, fastening systems of tool and a cutting material such as the type of the process (roughing, light roughing, wiping); the dimensional accuracy; the power burden of the technological system; the rigidity of the technological system; the size and the type of the material blank; the accuracy of the material blank; surface layer condition of the material blank (peel, scale pits, etc); the amount of the dimensional allowance properties of the work material; the diameter of the bore hole under conditions of the internal work; the direction of feed motion at each cutting pass; the work surface profile; technological features of the equipment (the efficiency of the spindle, the rotating frequency the maximum feed, the maximum diameter of the material blank, the maximum length of the material blank, the type and the size of the tool holder, availability of the metal-cutting compound); the maximum value of the depth-of-cut for each operation; surface quality requirements of the work part; the machining conditions (continuous interrupted and impact cut, constant and variable depth-of-cut); required productivity of the tool; required tool life.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):51-61
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Specifying perforated skin parameters in manufacturing honeycomb panels of soundproof structures
Molod M.V.
Abstract

The article describes the geometric characteristics and features of technology of constructive elements of welded, glued and brazed honeycomb panels used in sound-absorbing constructions channels air intakes and engine casings. Discusses the advantages and disadvantages of various methods for obtaining the perforation drilling electric discharge method: a method of punching sheet at press. Analyse the advantages and disadvantages of each method. In the technique and the dependences for determination of harvesting and the perforation zone boundaries, as well as forming process diagram of perforated paneling. The managing foiling program is developed to meet the geometry, kinematics of the punch press, mechanical characteristics and mathematical model of process of formation. This technique allows you to significantly reduce the number of signs of rejection of the process. One of the most important problems of forming plating method of covering is the uneven distribution of deformations on the surface of the workpiece. To solve this problem, the proposed method of reducing inequality deformation along the contour of the workpiece from the special inserts installed in the press.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):62-61
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Laser measurement systems for structural elements’ spacing check
Mordasov V.I., Sazonnikova N.A., Nonin A.S.
Abstract

In order to improve monitoring of the provisions of parts during assembly, final operations and subsequent operation the laser measuring system is designed to control the angular position of the structure. In relation to the task, it is necessary to realize a small-sized measuring rotary system providing high accuracy (error of not more than 1.5...2 angular seconds) when significant working distance between the test object and the autocollimator (up to 20 meters) and a relatively wide measurement range (10...12 angular. minutes). The method of "straight angled serifs" was constructed to solve this problem. Measuring channel implements a triangulation method. In accordance with the method of each video camera measures the viewing angles of the laser diode located at the checkpoint. Control surface areas has two phases: the control position of seats held without technological loads and after loading. In the result of the revealed analysis the following primary errors were established to determine the precision measurement of linear and angular coordinates of the test object: the measurement error of the coordinates of the center of the image of the measuring mark on the CCD matrix measuring opto-electronic transducer, due to noise and resolution the receiving area and the measurement uncertainty is determined by the deviation of the focal length of the lens from the nominal value.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):63-71
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Study of cycle life of a material in conditions of low-cycle fatigue and long-term strength
Bukatyi S.A., Okrugin A.A.
Abstract

Experimental studies shows that the main parts - the shaft and the disks of gas turbine engines, working in the conditions of low-cycle fatigue and durability, have a durability far exceeding the resource identified by calculation based on the hypothesis of linear summation of damage. Therefore, further clarification is needed calculation methods, allowing greater use of the reserves of strength parts. The performed research studies the influence on the durability of the increasing duration of zero cycle of loading samples with a period of T=200 s. and the restraint at the maximum and minimum levels: Dtmax=120 s. and Dtmin=60 s. The studies were performed on a standard round specimens with the diameter of the working area of 7.5mm. Shown that when you restrain a loading there is in the material proceeds relaxation process, combined with a deforming cyclic hardening and increasing of the plastic deformation. It was found that the hypothesis of a linear summation of static and cyclic components of the damage in the conditions of low-cycle fatigue and long-term strength is not confirmed. The increasing of the restraint in the loading cycle under the load to Dtmax=20 s. or more leads to a significant increase - up to 94 % of the static component of damage. The research results obtained during cyclic and repeated static loading, helped to confirm and substantiate the existence of a previously unknown “Effect of cyclic hardening materials”, due to the duration of the maximum load in the cycle of loading.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):72-77
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Efficiency of complex cycles of a gas turbine unit with varying degrees of heating in the first and second stages
Ivanov V.A.
Abstract

The method of finding parameters of complex cycle gas turbine with intermediate heating is created, provided that effective efficiencies of simple and complex cycles are equal and the degree of gas heating at the first and second stages is different. It is shown, that under the conditions of equality effective efficiencies of simple and complex cycles and decrease of the degree of gas heating at the second stage compared with that at the first one, the work and effective efficiency maximum is achieved at of the degree of increase of pressure is optimal in terms of effective efficiency (economic) for the simple cycle, which may be the function of the degree of gas heating both at the first and the second stage. It is found that under the conditions of equality effective efficiencies of simple and complex cycles, decrease of the degree of gas heating at the second stage and economic of the degree of increase of pressure determined as the function this of degree of heating, provides a higher work maximum compared with that achieved under economic of the degree of increase of pressure determined as the function of the degree of gas heating at the first stage.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):78-83
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Efficiency of complex cycles of gas turbine units with air bleed for the cooling of intermediate combustion chambers
Ivanov V.A.
Abstract

The possibility of effective efficiency increase of a complex cycle gas turbine with intermediate heating is considers provided that effective efficiencies of simple and complex cycles are equal, the degree of gas heating at the second stage is lower than that at the first one and the degree of increase of pressure the simple cycle is optimal in terms of effective efficiency (economic). The economic degree of increase of pressure is determined as the function of the degree of heating at the second stage, as it provides the maximum of work increase in the complex cycle compared with that in the simple cycle. The effective efficiency of the complex cycle with the selection of air for intermediate combustion chamber cooling is found by summing up the effective efficiency of the simple regenerative cycle for the part of air, selected on cooling, and that of the complex cycle with intermediate heating of the other part of the air. It is found that the effective efficiency of the complex cycle with the selection of air for intermediate combustion chamber cooling and its regenerative heating is higher than that without the selection of air and the effective efficiency of the complex cycle as well as the work of this cycle reaches its maximum at economic the degree of increase of pressure in the simple cycle.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):84-89
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Dependence of energy characteristics of Stirling gas refrigerating machines on external and internal parametric values
Belozertsev V.N.
Abstract

The question of forcing the heat engines Stirling is important. The increase of cold-productivity of the refrigeration machine is carried out by means of change of pressure filling and Internal parametric values of refrigerating machines: filling pressure, relative temperature, relative dead volume, the ratio of the maximum described volumes working cavities and external: frequency of rotation effects on the energy characteristics of machines. The article presents the assessment of the impact of these parametric values on the real characteristics of refrigerating machines and identify opportunities and ways of forcing speed of the drive. To work with minimum total power losses and maximum cooling capacity of the filling pressure and speed must not be changed arbitrarily. The relationship between them via the same minimum total losses in the regenerator.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):90-94
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Development of the construction of a gas turbine engine vane with built-in vortex tubes
Veretennikov S.V., Barinov S.N.
Abstract

This paper presents the results of numerical and experimental studies of heat transfer of swirling flows in channels and cyclonic vortex tubes using as a working medium of air and superheated steam. The research results of the calculation depends on the number of elements of the computational domain and on the time step. The experimental data were compared non-adiabatic of the vortex tube in air and water vapor. Numerical study of conjugate heat transfer vane turbine with two integrated eddy energy separators with superheated steam as a coolant. Given flow characteristic of the blade, the dependence of the cooling efficiency of the coolant flow and temperature distribution obtained in the material of the blade.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):95-102
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Examination of the theoretical possibility of creating a vernier electrorocket engine
Baigaliev B.E., Chernoglazova A.V., Tumakov E.A., Temnikova S.V.
Abstract

The report examines the possibility of creating a vernier electric rocket engine. All engines feature hightemperature combustion products from the engine nozzle that will be vented to the outside. The proposed motor will operate as follows: the working fluid (liquid) is supply through the porous insert into the combustion chamber via a gear pump. In fluid flow through porous insert, the liquid takes the temperature of the insert and may exceed it under certain conditions. These conditions are low porosity inserts (less than 0.05). The process will proceed in two stages. The first stage liquid is converted to steam, which is then heated to a temperature of the porous insert, and may exceed it as a porous insert can be used the porous materials made of a metal having a melting point from the melting point to the melting point of copper tungsten. In the second stage, the energy obtained in the first step is liberate in the nozzle apparatus for producing thrust. The energy input to the transformation from liquid to vapor and overheating by setting HDTV. Efficiency of these plants is 95%. Thus, the combustion chamber working fluid is at a temperature necessary to achieve the desired parameters of the rocket engine.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):103-106
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Development of thruster chamber operating on oxygen-hydrogen fuel
Salich V.L.
Abstract

The article presents the results of the development chamber thruster in the perspective oxygen-hydrogen fuel. Was established experimental model, whose main element is the chamber body, taken from the production engine and newly developed mixing head comprising a spark plug, fuel injectors, fuel manifolds, fittings for supplying fuel components, fittings for the pressure measurement. Ignition of the fuel mixture when starting chamber is electric plasma method. Fire tests were conducted camera manufacturer in terrestrial conditions on the experimental setup, which allows to measure the thrust, pressure in the combustion chamber and fuel reservoirs, determine the cost of fuel components. The test results are presented in the form of values of thrust, specific impulse, the coefficient of specific impulse at different total fuel mass flow and the fuel components ratio (different ratios of excess oxidant), suggest the achievement of acceptable energy characteristics. During the tests also confirmed the launch of a reliable chamber in a wide range of variation of the coefficient of excess oxidant confirmed efficiency of the engine during long hot work.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):107-112
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Increasing wear resistance of gas turbine engine blades on the basis of improving the process of thermoplastic hardening
Karpov A.V.
Abstract

The article describes a promising method for hardening treatment that improves the fatigue resistance of the surface layer of the blades of gas turbine engines (GTE), such as the thermoplastic hardening (TPH). It is shown the diagrams of a process for setting a hardening treatment. It is chosen the most rational modes of gas turbine engine blades hardening treatment plants for consideration for TPH. It is presented the principle of operation of installations for TPH and shown their basic design features. It is considered some types of equipment for the study of residual stresses and fatigue resistance. It is obtained the results of experimental studies of residual stresses and fatigue resistance for the consideration of plants for TPH. The results of the main conclusions are made: the greatest impact on the formation of residual stresses at thermoplastic hardening has the intensity of cooling, with an increase in which the value of residual stress increases; the optimum heating temperature is TPH 700 + 50 ° C and the pressure at the facility coolant cooling system with a controlled (1 - 1.5) MPa, the facility with the cooling system unregulated 0.54 - 0.6 MPa; hardening apparatus with controlled cooling system, as compared with hardening apparatus with irregular cooling system that increases the endurance limit at 3.5-5%, which prolongs the service life of the at 700-1000 hours.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):113-120
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Modeling of intrachamber processes in an oxygen-hydrogen thruster
Vaulin S.D., Salich V.L.
Abstract

The result of this work was the creation of the chamber thruster on the perspective oxygen-hydrogen fuel. In the process of designing the used ANSYS CFX system, which was implemented mathematical model of homogeneous multicomponent working body with the mixing and combustion. The calculations were performed on a supercomputer "Tornado" in South Ural State University. The simulation results of the first version of the chamber revealed a non-functional due to the high temperatures in the area of structural elements (external cooling was not provided), and therefore it was decided not to make this chamber. In the process of further computational studies chamber design being modified as long as it was not possible to achieve high combustion efficiency with the presence of structural elements near the zones with temperatures not exceeding the maximum allowed operating temperature of the material. Chamber manufacturer has passed fire tests, which confirmed its performance during long inclusions and showed acceptable power characteristics. It was also a satisfactory agreement between the experimental data with simulation results. Thus, the use of numerical modeling would eliminate the traditional to create new chambers long and costly phase of the comparative tests.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):121-130
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Iodine as an alternative propellant for electrojet engines
Ostrovskiy V.G., Smolentsev A.A., Scherbina P.A.
Abstract

In the article the analysis of iodine as a propellant electric propulsion for electric thruster with closed electron drift is provided. This compares the iodine thruster performance with the same parameters using the traditional propellant - xenon. Advantages of electro-propulsion on the iodine compared to installing, using xenon. Justified the use of iodine as a propellant for high power thrusters. Presents the preliminary design and the results of the first tests of stationary plasma thrusters on the iodine. The article provides information about the progress of RSC Energia corporate research, the purpose of which is to develop a bench-top system for the storage and supply of iodine. It is shown and described the system layout storage and supply for experimental testing electric propulsion on the iodine. Also shown plans of RSC Energia in further research on the development of electric propulsion on the iodine. The article presents a variant of the high power thrusters on a propellant of iodine, which offers the challenge of ensuring the life of the thruster and the use of thermionic cathode. This article provides an overview of Western achievements in the use of propellant iodine in electric thruster.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):131-136
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Mathematical modeling and investigation of the process of thermal theatment of aluminum ingots on the basis of regulated convective heat transfer
Gorshenin A.S., Krivosheev V.E.
Abstract

Existing cooling technology of cylindrical aluminum ingots don’t provide the same speed of the temperature in all parts of the ingots. The most appropriate use for cooling of ingots special camera. Existing calculation methods and modes of cooling, which take into account the geometric characteristics of the charge and a cooling chamber, and would provide the same cooling rate in all parts of the bars are missing. Therefore, the authors addressed the issue of mathematical modeling of the process of cooling aluminum ingots on the basis of the regulated convective heat transfer. When developing mathematical models were formulated assumptions, mathematical and physical formulation of the problem. The mathematical model included the analytical model of heat transfer in the system aluminum ingots - cooling air, the system of differential equations, initial and boundary conditions. A mathematical model has allowed to carry out an analytical study of the cooling process with constant and variable operating conditions and design factors such as the speed of the cooling air, the diameter of the bars and the height of the channel between the bars. An analytical study has allowed to formulate the algorithm, providing a nominal speed of each cooling of the ingot in a horizontal row by controlled cooling. To prove the validity of the analytical model was performed experimental study. The discrepancy between experimental data and analytical values averaged 34%.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):137-141
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Research of the validity of forecasting low cycle durability of gas turbine engine parts based on Manson’s equation
Porter А.M., Bukatyi S.A., Leshin D.P.
Abstract

The article presents the prediction of low-cycle durability of gas turbine discs and test samples by the method of universal tilt – on the basis of the Manson equation and its various modifications. Manson equation obtained by testing of standard specimens in stretching-compression, i.e. an uniaxial stress state and the symmetric cycle of loading. Under complex stress-strain state in the modification of the equations embeded the mean stress of the cycle, but clear guidance for determining it are missing. In this paper we proposed different ways to imagine the average stress. On the basis of verification of various modifications were adopted, the results of tests of standard specimens with circular cross-sections, samples of the lock "swallow's tail" cut from the disks of the compressor, as well as full-scale drive of new and used. The test was carried out from zero cycle of loading close to the real operating conditions of main parts of the gas turbine engine. By comparison of calculation results with the experimental data revealed the most effective ways to refine the Manson equations. It was found a significant effect on low cycle durability of not only the magnitude of deformation of the parts, but the type of stress-strain state. Therefore, the most effective was the using of the stress intensities. It was also established that the refinement equation, introduced by Manson and Muralidharan applicable only for stress states that are close to flat.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):142-150
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Estimation of static strength of sections of the linear pipeline portion with a colony of corrosion fine cracks
Subbotin V.A., Scherbo I.V., Kholodkov S.A., Giorbelidze M.G.
Abstract

This paper presents the proven analytical apparatus for determining the complex stress state in the material of the linear part -main pipeline with stress corrosion cracking in the form of fine crack colonies. The critical stresses are defined and an analytical dependence for calculation of the allowed internal pressure for the damaged pipeline, not satisfactory to strength conditions is received. The above calculation model of stress state is different from their counterparts in that it is not limited by standard methods based solely on the weakened section, and takes into account the stress concentration in the surface defect zone, which has a positive effect on the accuracy of estimated parameters. Introduced additional conditions during selection of permissible stresses ensures the correctness of strength calculations, especially in cases where there are corrosion cracks with relatively large depth in the pipe wall. Additionally, in the present method it is possible to consider the influence of the thermal component to the complex stress state. The presented theoretical apparatus was confirmed with finiteelement modeling in Ansys Mechanical software environment. The results of the practical implementation of this work are given recommendations on assessing the technical condition of pipes with crack defects of different nature, as well as determination of the maximum allowable working pressure, which meets strength conditions on gas pipelines susceptible to stress corrosion cracking.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):151-157
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Calculation of exciting aerodynamic load on a gas turbine engine compressor blade induced by the effect of a non-uniform gas flow
Ermakov A.I., Shklovets A.O., Fedorchenko D.G.
Abstract

Work is devoted to the creation of a design procedure of the exciting loads occurring on the impeller blades of GTE in situations of uneven circumferential gas load. The presence in the path of the engine bluff bodies, such racks engine mounts, causing substantial circumferential flow unevenness. Consequently, in blades having dangerous resonant vibrations that can lead to product failure. Determination of amplitude of the excited harmonics in the design phase will assess the severity of forced oscillations of the blades. The technique of determining the excitation of harmonics in the flow allows the calculation of the amplitude, to determine the impact of structural changes in the running of the engine on them. The finite element model consists of the inlet guide vane, rotor blades and bearing racks. Gas dynamic load is determined in units of rotor blades, but a small number of blades, eg for fan impellers, the accuracy of the excitation amplitudes of harmonics may be insufficient. Using the capabilities of Ansys CFX, gas-dynamic load is defined in additional areas path between the rotor blades. In work changing amplitudes of harmonics based on the number of measurement points of load.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):158-165
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Calculation of sleeve-shaped filter elements made of the MR material
Zhizhkin A.M., Lazutkin G.V., Volkova T.V.
Abstract

The article deals with the calculation of the characteristics of the thin-walled sleeve-type filter elements defined structural properties of the MR material. Existing results on the structural, filter, consumables and hydrodynamic characteristics of wire materials, the impact of their lifetime are fragmented and not linked to the calculation analytically closed form with the structural and technological parameters of the filter elements of the MR material. In the present paper we solve the problem of creating the calculation of the filter elements of the MR material with the specified filtering and hydrodynamic characteristics of the subject to the restrictions on the choice of dimensions and duration of use of the filter as a whole. The solutions of the fundamental problems to determine the structural and hydrodynamic characteristics of the MR material. The paper determines the possibility of creating a filter element, based on a given flow to ensure its performance and service life. We propose an algorithm for calculating the basic characteristics of the filter elements. It includes the solution of the system, and together with them the use of recommendations for selecting parameters of the structure and geometry of the MR material filter elements to ensure their desired filtering and hydrodynamic characteristics. This lets the rational parameters of the material structure with geometric MR material, filter and hydrodynamic characteristics of the filter elements. Such a generalized approach to the calculation of flow characteristics also provides an opportunity to take into account the life of the filter element. The use of the results is essential in the practice of creating high-performance filters based on thin-walled structures rational filter elements of bush type of woven wire MR material.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):166-174
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Experimental studies of shell vibrations
Lezhin D.S., Nagurnaya O.V., Nikulin E.V., Vergnano D.
Abstract

Results of modal analysis by ANSYS software for high pressure shaft of turbofan engine NK-8 are presented. Results of experimental researches of low modes and frequencies of the shell by photogrammetric complex ARAMIS HS are given as verification of calculations. The main attention is for experiment fulfillmentfeatures. For example, conditions of shell installation for free position of shaft are developed; different ways of researched shell vibration excitement are used. It gives a possibility of correct experiment for own frequencies obtaining. Comparison experiments for different values of crop-factor are fulfilled; analysis of information volume for obtained pictures is undertaken. Technology of researched object lighting for satisfactory image recognition for little exposure is developed. Methods of researched object photographing for complex algorithm of pictures switching are developed. It gives a possibility of experimental research of vibration processes which frequency is more than limit frequency of recording equipment. By these results an experimental methodic is developed and an experiment is fulfilled. First and second own frequencies are obtained experimentally; its values correspond to calculation results. In means that modeling of shaft in ANSYS software and boundary conditions are correct. Vibration modes for frequencies 211 Hz and 362 Hz are obtained. It corresponds to calculation results too. This research is fulfilled as a part of research of high pressure shaft of turbofan engine NK-8, as obtaining of correct model of boundary conditions (stiffness and damping of flange connection between shaft and disks of turbine and compressor) and influence of these boundary conditions on own frequencies and modes.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):175-183
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Experience in the development of 11Д58MФ liquid rocket engines
Smolentsev A.A.
Abstract

The article presents an analysis of the design work carried out in the design of liquid rocket engine (LRE) 11Д58MФ developed by JSC "RSC" Energy "for the upper stage (RB) ДМ. The developed liquid fuel rocket engine has a number of features that require innovative approaches to its design. The structure of the engine including experienced combustion chamber, the control system with functions for diagnostics and emergency protection, power supply of oxidizer and fuel tank with elements of devices that provide a guaranteed intake of propellants during his multiple inclusions, blocks thrusters operating on gaseous oxygen and providing impetus prelaunch booster and orientation in flight.The cooling chamber is performed without the use of liquid oxygen internal cooling is performed with a nozzle chamber with uncooled high expansion rationozzle. Workflow efficiency in the combustion chamber is provided by a slit mixing head, which uses the circuit components of mixed fuel: jet fuel into razing oxidant stream.Basic design and engineering solutions for combustion chamber: the use of a slit mixer-term head of the engine, performing geometry of cooling path with variable height, thickness and angle of the ribs to the axis of the chamber, the technology of manufacturing, assembly and soldering the mixing head and combustion chamber have been experimental testing. The LRE-linen design process was defined the composition ofpneumohydroautomaticequipment, small draft engines block, autonomous system universal and can be used in the development of similar engines.

VESTNIK of Samara University. Aerospace and Mechanical Engineering. 2014;13(5-4):184-194
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