The optimum model determination of porous barriers in high-speed tracks

2021 ◽  
pp. 095440972199532
Author(s):  
Masoud Mohebbi ◽  
Amir M Safaee
Keyword(s):  
High Speed ◽  
Fluid Dynamic ◽  
Rolling Stock ◽  
Force Coefficient ◽  
Porosity Level ◽  
Multi Objective Genetic Algorithm ◽  
Negative Effect ◽  
Optimum Type ◽  
Optimum Model ◽  
Boltzmann Method

In the railway industry, safety is an essential factor that has been modified by all societies and railroad managers. Against the background of increasing speed of rolling stock, risk factors such as cross wind and train stability have received more extensive attention. In this study, the porous wind barriers that are widely used in this industry have been surveyed. Also, to decrease the harmful effects of crosswind, the work attempts to find an optimum porous barrier design. This numerical simulation was based on a modern computational fluid dynamic in microscopic space model called the Lattice Boltzmann Method. Also, to find the optimum type of barrier design, the Multi-Objective Genetic Algorithm had been used. Two aspects of barrier design, including the porosity levels and distance between barriers, have been studied and, finally, a candidate design proposed for the barriers. It was found that porousity levels up to 15% have a positive effect in reducing the lift force coefficient, but beyond that it has a negative effect. On the other hand, increasing the porosity level leads to a decrease in the drag coefficient. The velocity vectors, velocity counter, vorticity, and turbulence intensity of the flow field around the model plotted for the candidate barrier.

Durability Analysis of the Reduction Gear for High Speed Train Considering Driving Histories

2012 ◽  
Vol 586 ◽  
pp. 269-273
Author(s):  
Chul Su Kim ◽  
Gil Hyun Kang
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Element Model ◽  
Rolling Stock ◽  
Reduction Gear ◽  
High Speed Train ◽  
Analysis Software ◽  
Tractive Effort ◽  
Durability Analysis ◽  
The Finite Element Model

To assure the safety of the power bogies for train, it is important to perform the durability analysis of reduction gear considering a variation of velocity and traction motor capability. In this study, two types of applied load histories were constructed from driving histories considering the tractive effort and the train running curves by using dynamic analysis software (MSC.ADAMS). Moreover, this study was performed by evaluating fatigue damage of the reduction gears for rolling stock using durability analysis software (MSC.FATIGUE). The finite element model for evaluating the carburizing effect on the gear surface was used for predicting the fatigue life of the gears. The results showed that the fatigue life of the reduction gear would decrease with an increasing numbers of stops at station.

scholarly journals Identification of Sleeper Support Conditions Using Mechanical Model Supported Data-Driven Approach

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3609
Author(s):  
Mykola Sysyn ◽  
Michal Przybylowicz ◽  
Olga Nabochenko ◽  
Lei Kou
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Dynamic Interaction ◽  
Theoretical Research ◽  
Rolling Stock ◽  
Monitoring Methods ◽  
Beam Dynamic ◽  
Track Geometry ◽  
Data Driven Approach ◽  
Support Conditions

The ballasted track superstructure is characterized by a relative quick deterioration of track geometry due to ballast settlements and the accumulation of sleeper voids. The track zones with the sleeper voids differ from the geometrical irregularities with increased dynamic loading, high vibration, and unfavorable ballast-bed and sleeper contact conditions. This causes the accelerated growth of the inhomogeneous settlements, resulting in maintenance-expensive local instabilities that influence transportation reliability and availability. The recent identification and evaluation of the sleeper support conditions using track-side and on-board monitoring methods can help planning prevention activities to avoid or delay the development of local instabilities such as ballast breakdown, white spots, subgrade defects, etc. The paper presents theoretical and experimental studies that are directed at the development of the methods for sleeper support identification. The distinctive features of the dynamic behavior in the void zone compared to the equivalent geometrical irregularity are identified by numeric simulation using a three-beam dynamic model, taking into account superstructure and rolling stock dynamic interaction. The spectral features in time domain in scalograms and scattergrams are analyzed. Additionally, the theoretical research enabled to determine the similarities and differences of the dynamic interaction from the viewpoint of track-side and on-board measurements. The method of experimental investigation is presented by multipoint track-side measurements of rail-dynamic displacements using high-speed video records and digital imaging correlation (DIC) methods. The method is used to collect the statistical information from different-extent voided zones and the corresponding reference zones without voids. The applied machine learning methods enable the exact recent void identification using the wavelet scattering feature extraction from track-side measurements. A case study of the method application for an on-board measurement shows the moderate results of the recent void identification as well as the potential ways of its improvement.

Improving the Efficiency of High-Speed AC Contact Suspension

2021 ◽  
Vol 5 (5) ◽  
pp. 39-43
Author(s):  
Maksim V. SHEVLYUGIN ◽  
◽  
Daria V. SEMENOVA ◽  
Keyword(s):  
Power Supply ◽  
High Speed ◽  
Single Phase ◽  
New Technologies ◽  
Alternating Current ◽  
Rolling Stock ◽  
New Materials ◽  
High Speed Railway ◽  
Electric Rolling Stock ◽  
Electrified Railways

When developing a high-speed contact suspension for railways electrified with alternating current, it is important to ensure that the electric rolling stock passes the neutral insert without turning off the current and without reducing the speed of movement. The article provides an analysis of previously developed devices in the field of power supply of electrified railways of single-phase alternating current, in which an attempt was made to pass an electric rolling stock of a neutral insert without disconnecting the load. The device of isolating coupling of a catenary and a neutral insert for high-speed railway lines electrified on alternating current is described. In this case, the passage of the neutral insert is carried out under current and braking of the electric rolling stock will not occur. Among other things, to improve the efficiency of high-speed contact suspension for railways electrified with alternating current, it is proposed to use new materials and new technologies that can be used in the device of insulating coupling of the catenary

scholarly journals Damping of vertical and horizontal transverse vibrations in the bridge span structures

2018 ◽  
Vol 216 ◽  
pp. 01015
Author(s):  
Darya Provornaya ◽  
Sergey Glushkov ◽  
Leonid Solovyev
Keyword(s):  
High Speed ◽  
Vibration Isolation ◽  
Seismic Protection ◽  
Rolling Stock ◽  
Railway Bridge ◽  
Vibration Damper ◽  
Dynamic Vibration ◽  
Bridge Span ◽  
Transverse Vibrations ◽  
Dynamic Damping

The paper considers the issues of vibration isolation of railway bridge units on high-speed lines and seismic protection using dynamic vibration dampers. The purpose of the research is to justify the efficiency of damping the dynamic vibrations of the bridge supports with seismic insulating support parts. The research methodology involves building mathematical models of the systems under consideration and their numerical analysis. The methods of structural mechanics and dynamics of structures were used for solving the assigned tasks. The basic mathematical dependences of the vibration system with two seismic masses were developed. The rolling stock was represented by concentrated forces moving along the span structure. As a result, a new scheme for dynamic damping of vibration of the bridge supports was proposed according to which the span structure used as the dynamic vibration damper has an additional fastening on a rigid abutment.

Thermo-Fluid-Dynamic Design of Reciprocating Compressor Cylinders by Fluid Structure Interaction (FSI)

2011 ◽  
Author(s):  
Riccardo Traversari ◽  
Alessandro Rossi ◽  
Marco Faretra
Keyword(s):  
High Speed ◽  
Fluid Dynamic ◽  
Fluid Structure Interaction ◽  
Classical Equation ◽  
Flow Coefficient ◽  
Reciprocating Compressor ◽  
Complex Situation ◽  
Fluid Structure ◽  
Associated Gas ◽  
Structure Interaction

Pressure losses at the cylinder valves of reciprocating compressors are generally calculated by the classical equation of the flow through an orifice, with flow coefficient determined in steady conditions. Rotational speed has increased in the last decade to reduce compressor physical dimensions, weight and cost. Cylinder valves and associated gas passages became then more and more critical, as they determine specific consumption and throughput. An advanced approach, based on the new Fluid Structure Interaction (FSI) software, which allows to deal simultaneously with thermodynamic, motion and deformation phenomena, was utilized to simulate the complex situation that occurs in a reciprocating compressor cylinder during the motion of the piston. In particular, the pressure loss through valves, ducts and manifolds was investigated. A 3D CFD Model, simulating a cylinder with suction and discharge valves, was developed and experimentally validated. The analysis was performed in transient and turbulent condition, with compressible fluid, utilizing a deformable mesh. The 3D domain simulating the compression chamber was considered variable with the law of motion of the piston and the valve rings mobile according to the fluid dynamic forces acting on them. This procedure is particularly useful for an accurate valve loss evaluation in case of high speed compressors and heavy gases. Also very high pressure cylinders, including LDPE applications, where the ducts are very small and MW close to the water one, can benefit from the new method.

scholarly journals Analysis and control of flow at suction connection in high-speed centrifugal pump

2017 ◽  
Vol 9 (1) ◽  
pp. 168781401668529 ◽  
Author(s):  
Wen-wu Song ◽  
Li-chao Wei ◽  
Jie Fu ◽  
Jian-wei Shi ◽  
Xiu-xin Yang ◽  
...  
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
High Speed ◽  
Internal Flow ◽  
Orifice Plate ◽  
Centrifugal Pumps ◽  
Pressure Area ◽  
Negative Effect ◽  
And Control ◽  
Experimental Data Analysis

The backflow vortexes at the suction connection in high-speed centrifugal pumps have negative effect on the flow field. Setting an orifice plate in front of the inducer is able to decrease the negative effect caused by backflow vortexes. The traditional plate is able to partially control the backflow vortexes, but a small part of the vortex is still in the inlet and the inducer. Four new types of orifice plates were created, and the control effects on backflow vortexes were analyzed. The ANSYS-CFX software was used to numerically simulate a high-speed centrifugal pump. The variations of streamline and velocity vectors at the suction connection were analyzed. Meanwhile, the effects of these plates on the impeller pressure and the internal flow field of the inducer were analyzed. Numerically, simulation and experimental data analysis methods were used to compare the head and efficiency of the high-speed pumps. The results show that the C-type orifice plate can improve the backflow vortex, reduce the low-pressure area, and improve the hydraulic performance of the high-speed pump.

scholarly journals Gas Turbine Train Development in France

1975 ◽  
Author(s):  
M. R. Garde
Keyword(s):  
Diesel Engine ◽  
Gas Turbine ◽  
High Speed ◽  
Rolling Stock ◽  
Lightweight Construction ◽  
The Future ◽  
Railway Traction ◽  
Aircraft Type ◽  
Very High

This paper presents a discussion on aircraft type gas-turbine train development. For railway traction purposes, the turbo-engines used on aircraft would improve the quality of the services provided in the electrified lines. The gas turbine should insure high speed and satisfactory acceleration. It would enable relatively lightweight construction to be carried out and run at a higher speed than trains on non-electrified lines. The gas turbine will not completely replace the diesel engine, but it will enable rolling stock to be constructed for which the diesel is unsuitable, especially in the case of high-speed, lightweight trainsets and, in the future, very high-powered units.

Simulation of Hypersonic Viscous Flow Past a 2D Circular Cylinder Using Lattice Boltzmann Method

2010 ◽  
Author(s):  
R. Kamali ◽  
A. H. Tabatabaee Frad
Keyword(s):  
Circular Cylinder ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
High Speed ◽  
Fluid Flows ◽  
Boltzmann Distribution ◽  
Equilibrium Distribution Function ◽  
Complex Flows ◽  
Compressible Viscous Flows ◽  
Boltzmann Method

It is known that the Lattice Boltzmann Method is not very effective when it is being used for the high speed compressible viscous flows; especially complex fluid flows around bodies. Different reasons have been reported for this unsuccessfulness; Lacking in required isotropy in the employed lattices and the restriction of having low Mach number in Taylor expansion of the Maxwell Boltzmann distribution as the equilibrium distribution function, might be mentioned as the most important ones. In present study, a new numerical method based on Li et al. scheme is introduced which enables the Lattice BoltzmannMethod to stably simulate the complex flows around a 2D circular cylinder. Furthermore, more stable implementation of boundary conditions in Lattice Boltzmann method is discussed.

scholarly journals World Experience in Creating Mathematical Models of Air Springs: Advantages and Disadvantages

2021 ◽  
pp. 25-42
Author(s):  
A. Y Kuzyshyn ◽  
S. A Kostritsia ◽  
Yu. H Sobolevska ◽  
А. V Batih
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Mathematical Models ◽  
Dynamic Behavior ◽  
High Speed ◽  
Vertical Direction ◽  
Rolling Stock ◽  
Air Spring ◽  
Advantages And Disadvantages ◽  
Mechanical Models

Purpose. Taking into account the production and commissioning of modern high-speed rolling stock, the authors are aimed to analyze the currently created mathematical models describing the dynamic behavior of the air spring, systematize them and consider the advantages and disadvantages of each model type. Methodology. For the analysis, a comparative chronological method was used, which makes it possible to trace the development of several points of view, concepts, theories. In accordance with the adopted decision equations, the existing models of air springs were divided into three groups: mechanical, thermodynamic and finite-elements. When analyzing mathematical models, the influence of a number of parameters on the dynamic behavior of the air spring, such as disturbing force frequency, heat transfer, nonlinear characteristics of materials, the shape of the membrane, etc., was considered. Findings. A feature of mechanical models is the determination of input parameters based on the analysis of experimental results, requires access to complex measuring equipment and must be performed for each new model of an air spring separately. Unlike mechanical models, which allow taking into account the damping effect of an air spring in the horizontal and vertical direction, thermodynamic models are mainly focused on studying the dynamic behavior of an air spring in the vertical direction. The use of the finite element method makes it possible to most accurately reproduce the dynamic behavior of an air spring, however, it requires significant expenditures of time and effort to create a finite element model and perform calculations. Originality. Mathematical models of the dynamic behavior of an air spring are systematized, and the importance of their study in conjunction with a spatial mathematical model of high-speed rolling stock is emphasized. Practical value. The analysis of the mathematical models of the dynamic behavior of the air spring shows the ways of their further improvement, indicates the possibility of their use in the spatial mathematical model of the rolling stock in accordance with the tasks set. It will allow, even at the design stage of high-speed rolling stock, to evaluate its dynamic characteristic and traffic safety indicators when interacting with a railway track.

scholarly journals HIGH-SPEED ROLLING STOCK OF UKRAINE

2021 ◽  
pp. 32-42
Author(s):  
О.М. Safronov ◽  
Keyword(s):  
High Speed ◽  
Brake System ◽  
Rolling Stock ◽  
Joint Stock Company ◽  
The European Union ◽  
Stock Company ◽  
Passenger Traffic ◽  
Technical Requirements ◽  
The World ◽  
Electric Train

A brief history of the development of high-speed passenger traffic in the countries of the world is shown, it is shown that the length of high-speed highways (SMM) in the world is 44 thousand km. Despite the fact that Ukraine is not included in the list of 28 countries with the SMM, a two-system electric train ECR1 "Tarpan" was created on the basis of the PUBLIC JOINT STOCK COMPANY "KRYUKOVSKY RAILWAY CAR BUILDING WORKS" (PJSC "KVBZ") for the speed of movement of more than 200 km / h. A description of the electric train and the peculiarities of the brake system are given. It is shown that the brake system corresponds to world counterparts for high-speed trains about what evidence test results, which, due to the lack of ATS, were carried out for a speed of 160 km / h. The results of the settlement research, using the mathematical model and the results of the driving brake tests, showed that the braking pathway of the electric train at a speed of 200 km / h is 1539 m, and at a speed of 300 km / h - 3172 m. The obtained brake path values comply with the technical requirements of the European Union TSI . Studies confirm that Ukraine has high-speed rolling stock for speeds up to 300 km / h. Key words: high-speed rolling stock, electric train, brake system, brake path, speed

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