Vol 13, No 1 (2014)
- Year: 2014
- Articles: 29
- URL: https://journals.ssau.ru/vestnik/issue/view/107
Full Issue
AIRCRAFT AND SPACE ROCKET ENGINEERING
Problems of unmanned spacecraft reengineering in abnormal flight situations and their knowledge-based solutions
Abstract
Problems and principles of reengineering during the development of onboard and ground distributed systems that control the survivability of Earth observation satellites are dealt with in the paper. Ideas of built-in and remote reengineering and refactoring are under development. Examples of reengineering techniques used for the development of Resurs-DK and Resurs-P unmanned spacecraft are presented.
9-21
Method of reducing design aerodynamic characteristics to the results of drain tests of a transport category aircraft model
Abstract
A method of reducing design aerodynamic characteristics to the results of drain tests by adjusting a mathematical model of the aircraft being designed on the basis of an aerodynamic prototype is presented in the paper.
22-29
Analysis of nonstationary thermal state of low-thrust liquid rocket engine with high-concentration hydrogen peroxide and kerosene propellant with film cooling
Abstract
The paper presents an analysis of the nonstationary thermal state of a low-thrust liquid rocket engine with HTHP (high-test hydrogen peroxide) and kerosene propellant with film cooling. A mathematical model was developed with internal convective and radiant heat fluxes. The model takes into account the heat flux pass through the wall. The results of the calculations show that in order to provide long working life of the combustion chamber wall it is necessary to use either 96% of HPK at the level of 20% of HTHP or 20% of kerosene needed for film cooling.
30-40
Analysis of nonstationary thermal state of a low-thrust liquid rocket engine taking into account injection, evaporation and combustion of liquid fuel droplets
Abstract
The physico-chemical state of reaction products in the combustion chamber of a liquid rocket engine of 500N thrust with account for the evaporation of liquid fuel droplets (highly concentrated hydrogen peroxide (96%) - and kerosene) and their combustion is discussed and analyzed in the paper on the basis of numerical methods. The software system “ANSYS Fluent” which is a universal program for the solution of thermohydraulic problems is used for the purpose.
41-55
Diagnostics of computer modules of the Superjet-100 aircraft using the method of boundary scan
Abstract
The article deals with the questions of search, localization and identification of manufacturing defects in printed boards of digital modules of the aircraft Superjet-100 avionics using the method of boundary scan.
56-67
Constructive actions for decreasing the acoustic pressure inside space-rocket products
Abstract
Possible measures for decreasing the whisper of pressure inside the reentry vehicle and intertank bay are outlined in the paper; a formula for calculating the total decrease of acoustic loading through the use of different measures is given.
68-79
Design of robust systems for the stabilization of unmanned aircraft equipment
Abstract
A model of a triaxial system for the stabilization and control of sight axis orientation of observation devices operated at unmanned aircraft is developed. The features of the robust structural synthesis procedure as applied to a system of the type analyzed are discussed. The results of the simulation of a synthesized system are presented.
80-90
MECHANICAL ENGINEERING AND POWER ENGINEERING
Method of calculating vibrations in a pipeline with damping supports made of MR material
Abstract
A method of calculating vibrations in a pipeline of an arbitrary shape with damping supports made of MR material with the help of the finite element method ANSYS software is developed. The method takes into account the non-linearity of MR material, it makes it possible to determine the amplitudes of pipeline vibration and the stress in the pipeline. The calculation results are confirmed by an experiment with the ARAMIS measurement system. The method can be used for placement of pipelines.
91-97
Development of a small-sized acoustic probe for the measurement of pressure pulsations in the gasdynamic duct of gas turbine engines
Abstract
The paper presents a mathematical analytical justification of the scheme of a small-sized acoustic probe of pressure pulsations insensitive to changes in the average pressure. An option of engineering implementation of a device for measuring pressure pulsations in high-temperature conditions is described. Amplitude-frequency characteristics of a small-sized probe at various values of the average pressure in the unit under test are given.
98-106
The use of regression models for estimating the standards of electric power losses in its transfer by territorial network companies
Abstract
The paper deals with the issue of forecasting electric power losses for a five-year period in conditions of RAB-regulation. The use of multicriteria regression analysis and systems of visualisation of the obtained data in order to take well-founded decisions is proposed.
107-111
Numerical investigation of gas dynamics in nozzles of small-dimensioned gas generators and flowing out jets
Abstract
The paper presents the statement of the problem of numerical simulation of gas dynamics of nozzles and jets of small-dimensioned gas generators of supersonic flows based on boundary layer and Navier-Stokes equations and the results of solving it. The results of the numerical studies of gas dynamics of nozzles and jets for standard small-dimensioned gas generators with a thrust 6 N and 12 N are given. Significant potential of increasing specific impulse by optimizing the contour of supersonic nozzles of small-dimensioned gas generators are exhibited. The process of shock wave formation in the supersonic part of the nozzle of a standard smalldimensioned gas generator is numerically investigated. Significant impact of shock waves on the gas dynamics of vacuum jets is illustrated.
112-122
Modeling static and dynamic characteristics of pressure reducing valves
Abstract
The article deals with mathematic simulation of static and dynamic characteristics of a pressure reducing valve installed at the outlet of a noise suppression device. A mathematical model implemented in Matlab/Simulink softwar complex is developed. As a result of simulation dependences of the main operating parameters of a pressure control valve on the area of the orifice flow section are obtained.
123-130
Calculation of hydrodynamic noise in the diffuser of a pulsation damper flow channel
Abstract
This article deals with the problem of hydrodynamic noise inside a fluid pressure vibration absorber. The calculation of hydrodynamic noise is based on the results of numerical simulation of fluid flow in the central duct of the vibration absorber. A complete system of hydrodynamics equations is solved with the help of a large eddy simulation turbulence model (LES).
131-143
Computer simulation of forming thin-walled t-tees
Abstract
The paper presents a new method of forming thin-walled t-tees. A finite- element software product ANSYS/LS-DYNA is applied to analyze the quality of the t-tees produced and to compare them with those obtained by flanging. The variation in thickness of t-tees is analyzed and the efficiency of the forming method proposed is confirmed.
144-149
Forecasting the endurance limit of surface-hardened cylindrical parts made of steel 20 by the initial deformations of reference specimen
Abstract
The possibility of forecasting the increment of endurance limit for solid and hollow cylindrical parts made of steel 20 with semicircular notches after outstripping superficial plastic deforming has been analyzed using the residual stresses (initial deformations) of a reference specimen hardened simultaneously with the part . It is established that the compressive residual stresses calculated in smooth parts by the initial deformations of the reference specimen differ insignificantly (less than 6%) from those found experimentally. The increments of endurance limits of hardened notched parts have been calculated by a well-known method using the average integral residual stresses criterion. It’s established that the design values of endurance limit increments differ from the experimentally found ones by no more than 15%.
150-158
Life time of vibration isolators made of MR material subjected to random loads
Abstract
A lifetime of vibration isolators made of wire MR material widely used in transport systems under random loads is analyzed. Dependencies of lifetime on dynamic and static stress, parameters of MR material (relative density, wire diameter) are obtained. The character of changes in vibration isolator parameters during its lifetime is analyzed. An equation for calculating the lifetime required for the design of vibration isolation systems with vibration isolators made of MR material is obtained.
159-165
Research of the mechanism of shock-inertial deposition of dispersed particles from a gas flow
Abstract
The analytical dependence describing the efficiency of shock-inertial deposition of particulate matter depending on the properties of the trapped particulate material and operating parameters of the gas purification process is obtained. The design of a new shock inertial action device that makes it possible to optimize the process of gas clearing taking into account the characteristics of the trapped components is developed.
166-172
Simulation and research of factors affecting aerodynamic indices of the gas purification process
Abstract
A mathematical model is developed that makes it possible to conduct numerical research of the influence of various factors on the hydraulic resistance of a centrifugal gas washer. Theoretical assumptions and a model combining aerodynamics, operating and design parameters of the apparatus are developed. An algorithm of calculating hydraulic resistance is proposed which is used in simulating the process of purification of gas emissions.
173-180
Study of thermal stability of microdisperse filler reinforced composites
Abstract
The article presents the results of studies of composite epoxy-filled materials reinforced with different fillers and aluminum-boric-silica microspheres carried out in a thermal gravimetric analyzer.
181-188
ELECTRONICS, MEASURING EQUIPMENT, RADIO ENGINEERING AND COMMUNICATION
Method of controllung the angular position of IO ASD relative to the system of coordinates of a gyrostabilized platform
Abstract
The paper deals with a method of determining and checking the angular deviation of the actual position of the optical astro-sighting device instrument (IO ASD) relative to its reference target position on a gyrostabilized platform (GSP). The structure of a three-degree-of-freedom gyrostabilizer (TGS) that makes it possible to solve the assigned problem is described. An algorithm of determining the angles of the actual position of the IO ASD on a GSP is presented. The results of verifying the method using the actual devices of the TGS are given.
189-193
Method of reducing speckle-interferometer sensitivity for the study of turbomachine elements vibration
Abstract
The article deals with the development of a method for obtaining time-averaged speckle-interferograms with a two-fold period of interference bands. An optical scheme allowing the increase of permissible vibration amplitudes of the analysed elements has been developed. Vibration characterictics of compressor stage 5 blades are subjected to comparative analysis with the use of both the developed method and the traditional methods. The diagram of compressor blade leading edge vibrodisplacements is made up on the basis of the data obtained.
194-200
Allan variance-based assessment of basic characteristics of a strapdown inertial sensing unit
Abstract
The article describes the use of Allan variance method for analysing noise terms of output signals of pendulous accelerometers and fiber-optic gyroscopes in a strapdown inertial unit. The results obtained via the Allan variance method are compared to the parameters specified in the equipment certificate.
201-209
Sensor equipment “Shtil-M” for carrying out experiments on the “Resource-P” spacecraft
Abstract
Sensor equipment «Shtil-M» is described which is designed to monitor the magnetic environment of the “Resource-P” spacecraft with six three-component magnetometer sensors, to measure the magnetic field vector with a three-component magnetometer sensor, and to control the noise in power lines and possible electrostatic discharge registration. The results of measurements of the observed values are given.
210-221
Implementation of hardware-software filtering in a measuring converter of the arterial pulse signal
Abstract
The paper deals with a technique of hardware-software filtering implemented in a measuring converter of the arterial pulse signal. As a result of research the optimal pass band of a digital filter and optimal cut-off frequency of a hardware high-pass filter were determined. The metrological characteristics of a photometric measuring converter of the arterial pulse signal were investigated. The instrumental errors of measurement of amplitude-time characteristics of the recorded arterial pulse signal were determined.
222-228
CONTROL, COMPUTER SCIENCE AND INFORMATION SCIENCE
Research of textural features for the diagnostics of nephrological diseases using ultrasound images
Abstract
A method of automated diagnostics of kidney diseases using ultrasound images is proposed. The efficiency of different groups of information features of such images for the task of recognition is analyzed. According to the data of a number of experiments on real data the group of two Haralick’s features showed the best result. The estimation of probability of wrong recognition for that group was 0.06. Spectral correlation features also demonstated high efficiency, the estimation of the latter for them being 0.10.
229-237
Comparative modelling of laser beam propagation in a uniaxial crystal based on integral operators
Abstract
A comparative numerical calculation of propagation of Gauss-Laguerre and Bessel laser modes in an isotropic medium and in a uniaxial crystal by means of integral propagation operators based on the plane and spherical wave expansion is presented.
Numerical simulations with different types of beam polarization and different position of the crystal axis has made it possible to determine the conditions under which the greatest astigmatic distortion of the beams takes place. The analysis may be useful in practice to determine the position of the crystal axis.
238-252
Controlled percolation and optimal two-phase operations in large-scale networks of nanosatellites
Abstract
The paper deals with the solution of applied problems with the help of clusters of simple nanosatellites (NS) united in a network, each of them incapable of onboard control of the center-of-mass motion and randomly distributed in a given area of coverage of a ground track interval.
If this method of receiving information is used the set of NSs is required not only to study the characteristics of each NS but also to consider the characteristics of large-scale random clusters of objects forming a "complex network". The notion of controlled percolation of the coverage region implemented in two phases is introduced. During the first phase the stochastic base with comparatively small concentration of NSs is formed which does not provide stochastic percolation, while during the second one additional nanosatellites are introduced in intercluster intervals in an optimal way to achieve the shortest percolation path through stochastically formed NS clusters with a relatively small total number of NSs and minimum of total costs.
253-266
Error distributions in aircraft position determination
Abstract
The paper deals with the problems of determining aircraft coordinates. The widely used Gaussian distribution does not make it possible to analyze extremely rare events with certainty. The ICAO- recommended double-exponent distribution does not meet the requirements of accuracy either. It is, therefore, necessary to look for new distributions. The paper gives examples of such distributions as well as examples of solving problems of detecting violations of separation.
267-274
Influence of subwave details of microrelief on the diffraction pattern of gaussian beams
Abstract
The paper deals with the influence of subwavelength details with two types of etching of microrelief (ridge and groove) on the diffraction pattern. Modeling the diffraction of uniform-polarization radiation corresponding to both a Gaussian beam and a vortical Gaussian-Laguerre beam is performed by the method of solving Maxwell equations by finite differences in time domain (FDTD). The characteristics and features of the diffraction pattern in the near zone, including those connected with the formation of the longitudinal component of the electric field are determined.
275-286