Vol 26, No 4 (2018)

Informatics, Computer Science and Control
System analysis and modeling of environmental efficiency of regional power grid: the case of Samara region
Ivanova D.V.
Abstract

Study of power grid activity has been mainstreamed not only in terms of productive, but also in environmental aspect, reflecting the impact of power grid on environmental. Analysis of infrastructural model of Samara region industrial system showed, that enterprises of power grid have multiple connections with industrial enterprises of Samara city and Samara region. This fact highlights the need for exploration of power grid activity in conjunction with this manufacturing and economic systems. A control algorithm for the activity of a regional power grid system of Samara in conjunction with region and city manufacturing and economic systems was developed. The mathematical modelling of power grid activity was carried out with the help of Cobb-Douglas production functions. Double loops simulation control system which allows to explore ways of enhancing the economic and environment efficiency of regional power grid has been built. Proposed scenarios of power grid functioning and their environmental impact were analyzed. Recommendations on the management of activity of object could be applied on industry branch (region power grid) level as well as on industry region level (regional industrial complex).

Vestnik of Samara State Technical University. Technical Sciences Series. 2018;26(4):6-18
views
Using ENO algorithms of spline interpolation for oil boiling curves modeling
Konygin S.B., Kryuchkov D.A.
Abstract

This paper is about oil boiling curves interpolation used in the gas and oil refining processes modeling. Authors of this paper offer to use ENO splines for the approximation of boiling curves with few experimental points. It allows to exclude oscillations of the interpolation polynom and the occurrence of components with the negative fractions. This idea was realized in the program platform for modeling and calculation of the processes and devices “MiR PiA”. The testing of these ENO algorithms using one example has shown the convergence between the modeling results and the experimental data. Furthermore, ENO splines can be used for creating the boiling curves from the stream compositions.

Vestnik of Samara State Technical University. Technical Sciences Series. 2018;26(4):19-28
views
The method of assessment the competence of experts
Marycheva P.G.
Abstract

The paper presents experts qualification assessment, its importance and productivity, selection of experts for the expert evaluation at the project planning stage. The analysis of literature, scientific publications, existing solutions and methods for assessing the competence of experts using the hierarchy method is carried out. Criteria, accurately reflecting the characteristics of this expert are proposed, how suitable it is for this expert evaluation, which allow the most effective assessment of its competence. The application of the method of analysis of hierarchies is considered to solve this problem its positive and negative sides regarding the application of the competency assessment. The qualification assessment method was developed using analytic hierarchy process elements. Decisionmaking behavior was described with application of developed method; competence affecting factors also were described, such as work experience, number of successfully completed expert ratings, compliance of education with the scope of work, and workgroup characterization. An example of calculation by the developed method is given, selection of the most suitable expert, according to the offered characteristics the comparison of calculations by the developed method with the classical calculation method of analysis of hierarchies. Exemplified the developed-method calculation, was made a comparison with classical hierarchy analysis method. The proposed method has the necessary accuracy and a small relative error and can be used to assess the competence of experts and other tasks to which the hierarchy analysis method is applicable.

Vestnik of Samara State Technical University. Technical Sciences Series. 2018;26(4):29-40
views
Mechanism of target search and information collection on scientometrical indicators as a support tool of managing solutions in formation of personnel reserve of the university
Chekotilo E.Y., Kichigina O.Y.
Abstract

In this paper vision of the personnel management system of the university is presented. Subsystem of planning, searching and selection of scientific and pedagogical personnel is considered separately. The effective practices of attracting leading scientists and talented youth to work at the University are listed. The analysis of the main criteria for assessing the individual performance of scientific and pedagogical employees. As a support tool of managerial decisions at the stage of search and selection of scientific and pedagogical personnel, a mechanism and implementing its software has been developed, which allows automating a time-consuming process of collecting information and database filling about prospective job seekers. The choice of input parameters of search procedures is based on the modern requirements of the higher education system of the Russian Federation to the effectiveness of universities and personal performance of scientific and pedagogical employees of these organizations. The described mechanism allows real – time search and collection of information from open official Internet resources. The search procedure consists of two stages. At the end of the first stage, a database of scientists – potential candidates for vacant positions, the area of scientific interests of which lies in a given direction. As a result of the second stage, the primary data are supplemented with scientometric indicators of their activities. Received information allows to fully assess the scientific potential of the scientist and can be used not only for the formation of the personnel reserve of the organization, but also in making decisions on the development of a dissertation councils network of the University.

Vestnik of Samara State Technical University. Technical Sciences Series. 2018;26(4):41-51
views
Instrumentation, Metrology and Informative-measurings devices and systems
Structure and operation algorithms of the systems for measuring of radial clearances with temperature self-compensation
Belopukhov V.N., Borovik S.Y., Kuteynikova M.M.
Abstract

The paper is dedicated to the principles of construction of the systems for measuring of radial clearances in compressors of gas-turbine engines. The methods realized in such systems are based on using of single-coil eddy-current sensors with sensitive elements made as a conductor strips and self-compensation of temperature influences on the sensor. The method also involves the using of only one sensor (it provides work and compensation functions) and as a result only one hole in the engine stator. The selfcompensation procedure is carried out in operation mode during rotation of the rotor. It involves measuring and fixing of extreme values of equivalent inductance of primary winding of matching transformer of single-coil eddy-current sensor at the moments when the controlled blade is in sensor sensitivity area and when the blade is out of it (when sensor’s sensitive element is in interblade zone) and further difference calculation between obtained results. This difference doesn’t depend on temperature influence on sensor constructive elements. Because of this self-compensation there is no need in additional sensor for temperature correction an as the result there is no need to make additional hole in engine stator. Hence the proposed method is better compared to existing. The article considers the general structural and functional scheme of the system that realized the method with temperature self-compensation. The main operation algorithms of the system such as the algorithm for seeking of extreme codes in interblade zone, the algorithm for difference calculation between codes with the removal of “non-compensated” temperature influences on the sensor and the algorithm for blades numbers detection during asynchronous sensors surveying are given too.

Vestnik of Samara State Technical University. Technical Sciences Series. 2018;26(4):52-65
views
Analysis of metrological characteristics of the thermovision technical diagnosis system containing a neural network
Girin R.V.
Abstract

The paper deals with the problem of determining the errors of the thermovision system of the electronic devices technical diagnostics using a neural network. The structure of the system is described, including measuring channels with a thermal imager, an external thermometer, a block of computational models of thermal states, a knowledge base and a software neural network thermogram analyzer. It is proposed to use for the analysis of device states the two-branch network consisting of the multilayer convolutional neural network and the fully connected network. A metrological model of measuring channels has been built. A classification of the components of the instrumental error is given and expressions for the multiplicative and additive components of the instrumental error are obtained. Particular attention is paid to the analysis of the methodological error caused by the use of an artificial neural network in the classification of failures in the device. Experimental studies were performed that confirmed the effectiveness of the proposed methodological and technical solutions.

Vestnik of Samara State Technical University. Technical Sciences Series. 2018;26(4):66-81
views
Method of signal approximation in differential scanning calorimeter
Nechaev A.S., Zhirnova A.P., Nechaeva I.N.
Abstract

The paper analyzes the methods of reconstructing time-local information signals used in differential scanning calorimeters (DSC) and makes a choice on wavelet functions. Based on the selected maternal wavelet, a technique was proposed for approximating the signals obtained experimentally with a DSC device. Approbation of the technique for single-peak and two-peak signals was carried out. Having the possibility to change the parameters of the approximating function in the course of the mathematical description of the signal, the possibility of using the technique for working with substances possessing endo- and exothermic properties at the time of the phase transition was proved. Evaluations of the effect of digitizing the signals on the accuracy of the measured differential temperature were given. As a result, the relative error was estimated by the approximating function when using the proposed technique from the number of iterative calculations performed.

Vestnik of Samara State Technical University. Technical Sciences Series. 2018;26(4):82-91
views
Automatic determination of viscosity by rotary viscosimeter VRTS
Korganova O.G., Kuznetsov V.A.
Abstract

If it is necessary to determine the viscosity at a given temperature, various viscosimeters of various types, mostly rotational viscometers can be used. One of them was developed at the Department of Measuring Technique of Samara State Technical University. It contains two channels: a viscosity measuring channel and a temperature measuring channel. Rotation of the measuring rotor is carried out by a drive through a calibrated spring, the angle of twisting of which is proportional to the torque, which is converted into a pulse-width signal. The microcontroller measures and analyzes this signal and a signal proportional to temperature, converts them into a digital code and outputs the information on viscosity and temperature through the output port in a digital form.

Vestnik of Samara State Technical University. Technical Sciences Series. 2018;26(4):92-101
views
Electrical Engineering
Statement of problem from computational fluid dynamics of electromagnetic bearing cooling of a gas compressor unit
Ivannikov Y.N., Makarichev Y.A.
Abstract

Dynamic of electromagnetic bearing incorporation in the capacity of a supercharger for the gas compressor unit (GCU) from PAO “Gazprom” demonstrates incremental increase beginning from 2005. Wherefore problem of electromagnetic bearing (EMB) performance build-up (reliability growth, power reduction, mass reduction, dimensional specifications reduction etc.) become progressively important. As a consequence, thermal effect problem along of specific electromagnetic load increase become on the front burner. Magnetic, thermal and fluid dynamic numerical simulation by finite-element method by custom-made software allows computational accuracy to advance as consequence reliability GCU. The results of geometry model EMB analysis for the gas compressor unit presented in this paper. It is educed singularity of heat carrier flow in cooling system of electromagnetic bearing. Near-wall modeling approach for turbulence flow and the most relevant turbulent model was analyzed. The turbulence mode and near-wall approach was selected according to operational features of electromagnetic bearing, an introduction was given for meshing and boundary conditions were determined.

Vestnik of Samara State Technical University. Technical Sciences Series. 2018;26(4):102-113
views
The mechatronic module as part of the automatic control sistem
Lysov V.E., Peshev Y.I., Khamitov Z.K.
Abstract

The problem of improving the functional possibilities of sensitive jig-boring and jig-grinding machines, as well as their accuracy and productivity, is considered in the article. It is shown that essentially the problem is solved by setting the work piece onto the rotary table which is locked on the worktable of the machine. The rotary table is a mechatronic module in which the electric engine and the mechanical part (plate) are constructively united into a single unit. The exclusion of the dead zone in the kinematic chain and the possibility of processing the piece in different points make it able to solve the set tasks. The structural scheme of the mechatronic module and the recommendations of developing the system of its automatic control are provided.

Vestnik of Samara State Technical University. Technical Sciences Series. 2018;26(4):114-121
views
Position control of temperature of electric resistance furnace
Osipov V.S., Danilushkin A.I., Bazarov A.A.
Abstract

The problem of determining the frequency and amplitude of temperature fluctuations of the heating furnace by resistance at positional regulation with the help of unipolar ideal relay and relay with loop characteristic is considered. The aim is to optimize the operation of the two furnaces in the power supply system so that the furnaces are not switched on simultaneously in the temperature stabilization mode. In the literature, as a rule, simplified examples of tracking systems with the use of an ideal relay are considered, various methods of accurate and approximate methods for determining the frequency and amplitude of symmetric oscillations are given, however, with asymmetric oscillations, taking into account the displacement, the most acceptable is the algebraic method using the harmonic linearization method, with the dependence of the frequency and amplitude of the oscillations on the relay characteristic loop parameter in order to assign this parameter at an acceptable temperature deviation. The coefficients of the harmonic linearization of a relay with a loop characteristic with allowance for bias are complex expressions involving the amount of displacement. To simplify the calculations, the limiting variant is adopted, when the magnitude of the amplitude of the oscillations is equal to the sum of the displacement and half the width of the relay loop.

Vestnik of Samara State Technical University. Technical Sciences Series. 2018;26(4):122-134
views
Calculation of parameters of a linear asynchronous motor for a melt mixing system
Pevchev V.P., Strizhakova E.V., Ovsyannikov V.N.
Abstract

A set of questions on the modeling of electromagnetic processes in a linear asynchronous motor, which is a system containing a stator winding, a steel furnace body and a molten metal, is considered. Effective mixing of the liquid metal is realized in a singlephase power supply mode of the stator winding. For the linear movement of the melt, which is required when slag is charged, two-phase voltage is used. The calculation of the controlled field of electromagnetic forces, providing the circulation and linear displacement regimes, was carried out numerically. The large gap between the stator and the melt and the presence of a steel shell between them lead to low values of efficiency and power factor. The search for a favorable relationship between the width of the groove and the tooth is made taking into account the restrictions on the allowable values of induction in the magnetic circuit, heat loss and voltage in the stator winding. The complexity of the geometric design makes it difficult to use the procedures built in the calculation program for finding the optimal parameters of the designed device. The presence of ferromagnetic materials in the stator design causes a complex relationship in the distribution of electromagnetic fields and heat sources inside the shell. Analysis of heat losses at the edges of the stator winding led to the need to reduce the size of the conductor due to the significant uneven distribution of current. The choice of the frequency of the voltage produced on the basis of a comparison of the nature of the movement of the melt under the action of electromagnetic forces. High-quality mixing is achieved when large vortices are formed that capture the entire lower layer of the melt, which is ensured by increasing the stator length. In the download mode, the formation of two layers in the melt, moving towards each other, is beneficial. The calculations showed a linear dependence of many parameters of a linear motor on the ratio of the width of the tooth and the groove for the region of unsaturated iron of the magnetic circuit.

Vestnik of Samara State Technical University. Technical Sciences Series. 2018;26(4):135-144
views
Improvement of schemes for connection of three-phase asynchronous motor to a single phase network
Kharlamov V.V., Galkin A.G., Moskalev Y.V., Lysenko V.S.
Abstract

In the paper the review of technical devices for connection of a three-phase winding of the stator of the asynchronous motor to a single-phase network is carried out, their main advantages and shortcomings are considered. A theorem on obtaining a threephase symmetric stress system using two single-phase sources of electromotive force is presented and proved. On the basis of the proved theorem the electric scheme for connection of a three-phase stator winding of the asynchronous motor to a single-phase network is offered. In the article authors calculate currents, active and reactive power, the power factor of the two single-phase sources of electromotive force and an asynchronous motor when changing the slip in the operating range. The phase resistances of the asynchronous motor were determined using an L-shaped equivalent circuit. In the program package Matlab Simulink was carried out simulation of the induction motor connected by means of the schema under consideration. For the practical implementation of the proposed scheme as one single – phase AC voltage source can be used single-phase network, as the other – a semiconductor converter connected to a single-phase network.

Vestnik of Samara State Technical University. Technical Sciences Series. 2018;26(4):146-157
views

This website uses cookies

You consent to our cookies if you continue to use our website.

About Cookies