Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan

About: Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan is a education organization based out in Dnipro, Ukraine. It is known for research contribution in the topics: Track (rail transport) & Bogie. The organization has 736 authors who have published 655 publications receiving 1468 citations. The organization is also known as: Institute of Railway Transport Engineers.

Simulation of the accidental pollution after the emergency in to the storage of rocket solid propellant

Abstract: Purpose. Development of the operational numerical model to compute contamination of the atmosphere over Pavlograd city in the case of solid rocket propellant ignition at the storage. Methodology. To simulate the toxic chemical dispersion (product of the solid rocket propellant firing) the equation of convective-diffusion transfer is used. This equation takes into account the toxic chemical dispersion in the atmosphere by wind and the atmosphere diffusion. To calculate the process of the indoor contamination in the case of the contaminated air infiltration a balance model is used. This model takes into account the ventilation flow rate, volume of the room, concentration of toxic chemical in the inlet air. To compute the ventilation flow rate the empirical model was used. The implicit change–triangle difference scheme was used for the numerical integration of the governing equation. FORTRAN language was used to develop code on the basis of the created numerical model. On the basis of the developed numeral model numerical experiment was carried out which allowed to estimate the level of atmosphere contamination in Pavlograd city. Findings. The operational model allows predicting quickly the hitting zone dimensions. The developed model was used to estimate risk of people toxic hitting in the residential districts of Pavlograd city. Originality. A numeral model allows to estimate the risk of toxic hitting of people in Pavlograd city in the case of an accident at the of solid rocket propellant storage. Practical value. The developed numeral model can be used for the quick estimation of risk for people in the city after toxic chemical release at the solid propellant storage. The developed numerical model solves the problem to assess the consequences for the population at ignition of solid rocket propellant in storage.

About the use of universal magnetic characteristics to calculate the electromechanical characteristics of traction motors

Abstract: The idea of increase the calculations exactness based on application of universal magnetic characteristic due to value variation of satiation factor is considered.

Development of criteria of charge and discharge efficiency of solid state of heat accumulator

Abstract: Purpose . Development of similarity criteria for different modes of operation of the solid-state heat accumulator working due to accumulation of heat in the volume of the heat storage material without phase transition, and the creation of systematic criteria of heat accumulator efficiency for determination the weight / size parameters and operating modes at the design stage. Methodology . To achieve the objectives of the study the theory of similarity and dimensional analysis were used as well as planning and carrying out techniques of physical experiments. Findings. Based on the theory of similarity and dimensional analysis similarity criteria operation of solid-state heat accumulators, under given basic parameters were obtained. These are performance criteria for charge, discharge and full criterion. Three theorems of similarity theory in application to the solution of engineering problems were used. The criterion of efficiency of the heat accumulator charge characterizes the effectiveness of achieving the specified value of the specific amount of heat in the material of heat accumulator under charge, under received materials, geometrical ratios, and heat flow of the heat input. The efficiency criterion characterizes the discharge efficiency of the heat accumulator, at the accepted materials; mass of heat-retainer and the total accumulated amount of heat when the value of the heat flow and the time of discharge. Full coefficient of the heat accumulator performance characterizes the efficiency of the heat accumulators for a full cycle. Originality. Accordingly to the analysis the implementation of any system of solid-state heat accumulator is possible on the basis of structural schemes of this type of device. The similarity criteria of the efficiency of the charge, the efficiency of discharge and the full criterion of solid-state heat accumulators’ efficiency based on the solid storage material without phase transition were obtained. Practical value. Criteria presented in this work are of a comparative nature. In accordance with the obtained criteria we can compare designed and existing heat accumulators that are similar to structures. Feasibility analysis indicates that the proposed assessment methodology of solid-state heat accumulators’ efficiency in different modes of operation is effective, technically feasible and allows determining the weight / size parameters and modes of operation of the solid-state heat accumulator at the design stage.

Study of the manual power equipment of traction electrification system of the railways

Abstract: Purpose. Investigation of the operation of power equipment of traction substations (TS) of Ukrainian electrified railways. The search of the new modern methods and approaches improved monitoring, diagnostics and maintenance of power equipment TS during operation to maintain the required level of reliability of the traction power supply of electrified railway and limit the power equipment accidents TS. Methodology . The study of changes of a technical condition of TSs ’ equipment over the last 11 years was done for achieving this goal. This research was done for solving problems of power supply railways with high quality on the base of the reports analysis of the management and power supply of Ukrzaliznytsia. Findings. It was found that on the base of the new methods of maintenance is the risk analysis of old equipment or equipment with some defects (rev servicing equipment for the actual technical condition).Reliable performance of power supply devices has significant impact for solving the problem of safety on the railways of Ukraine. Different kinds of accumulated damage are at the first place before of failures of an electric power supply of electrified railway. The study of main causes of violations from 2002 to 2012 year showed that 80% of the reasons disorders normal operation of the traction power supply over the period constitutes next factors. There are damage to the main power equipment TS; power off the grid; overload and surge; and the impact of weather conditions. The primary power equipment failure of TS are constituted about 43%. Relevant constant monitoring, testing and diagnostics of the equipment with the creation and use of micro-processor smart automated monitoring and diagnosis are topical in the current operating conditions. Originality. The new directions for further improvement of maintenance electrified traction substations for electrified railways were considered. Modern strategies and management techniques and maintenance TS electrified railways of Ukraine were proposed at the first time. This methods aren’t covered in the "Instructions for maintenance and repair of equipment of traction substations, power points and sectioning electrified railways ’ IT-0024. The basic problems for implementation of these strategies were identified. Practical value. It was established that system outage under tight central planning and management in the new economy does not provide, in many cases, approval and adoption of effective and optimal solutions in organization and carrying out maintenance. It was investigated that a significant portion of electric power equipment of TS even after normative life maintains its performance under the terms. There are allowable stress regimes, timely testing, diagnosis, maintenance, repair and quality of execution; on the other hand the service life of electrical equipment depends on its residual life.

Losses of recovered electric energy in the elements of a DC electric transport system

Abstract: The regenerative braking is one of the most attractive ways for energy saving in electric transport. It has many advantages and its effectiveness is discussed in numerous researches, but there are no significant publications, which describe the power losses in the way of recovered current flowing. The paper describes an alternative method for estimating recovered energy losses in the elements of a DC electric transport system. In comparison with existing methods, it is based on the correlation theory of stochastic processes and takes into account the Fryze's concept for reactive power. The method is verified by the experimental researches, which are performed for the VL8, VL11M, VL11M6 locomotives, EPL2T multiple-unit train and T4D tram, which operate in DC sections, Ukraine. The losses are calculated for different elements of an electric transport system, and their theoretical and statistical distributions with basic probabilistic characteristics are shown. The results prove the validity and applicability of the method.