Numerical study of the air flow through an air-conditioning unit on high-speed trains

2019 ◽  
Vol 187 ◽  
pp. 26-35 ◽  
Author(s):  
Xueliang Li ◽  
Fan Wu ◽  
Yu Tao ◽  
Mingzhi Yang ◽  
Robert Newman ◽  
...  
Keyword(s):  
Air Conditioning ◽  
High Speed ◽  
Numerical Study ◽  
Air Flow ◽  
High Speed Trains ◽  
Flow Through

scholarly journals Design and Fabrication of Two Step Speed Control of a Cylinder Circuit using Pneumatics

2019 ◽  
Vol 8 (6S2) ◽  
pp. 512-516
Keyword(s):  
Flow Control ◽  
High Speed ◽  
Air Flow ◽  
Control Valve ◽  
Speed Control ◽  
Flow Control Valve ◽  
Push Button ◽  
Low Speed ◽  
Flow Through

The main aim of our project is to design and fabrication of pneumatic two step speed control of a cylinder. Initially the flow from the FRL retracts the cylinder when the push button is in its spring offset position. When it is pushed the flow pilots actuate. The air passes through the flow control and shuttle valve. Then the cylinder extends with high speed as the valve allows more air to enter the cylinder. When the piston reaches the position it operates the cam push button and pilot air flow through this and actuate 5/2 pilot operated valve and reaches flow control valve which permits less air. Then the flow through enters the shuttle valve to cylinder and allows the cylinder to extend at relatively low speed. At the end of extension stroke deactivating push button retracts the cylinder. Thus the speed of cylinder is controlled and project can be achieved

scholarly journals Active Control of Contact Force for a Pantograph-Catenary System

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Jiqiang Wang
Keyword(s):  
Active Control ◽  
Contact Force ◽  
High Speed ◽  
Large Scale ◽  
Vibration Suppression ◽  
Numerical Study ◽  
Primary Objective ◽  
Geometric Framework ◽  
High Speed Trains ◽  
Catenary System

The performance of the high speed trains depends critically on the quality of the contact in the pantograph-catenary interaction. Maintaining a constant contact force needs taking special measures and one of the methods is to utilize active control to optimize the contact force. A number of active control methods have been proposed in the past decade. However, the primary objective of these methods has been to reduce the variation of the contact force in the pantograph-catenary system, ignoring the effects of locomotive vibrations on pantograph-catenary dynamics. Motivated by the problems in active control of vibration in large scale structures, the author has developed a geometric framework specifically targeting the remote vibration suppression problem based only on local control action. It is the intention of the paper to demonstrate its potential in the active control of the pantograph-catenary interaction, aiming to minimize the variation of the contact force while simultaneously suppressing the vibration disturbance from the train. A numerical study is provided through the application to a simplified pantograph-catenary model.

Experimental Investigation of Air Vortex Interaction With Porous Screen

2014 ◽  
Author(s):  
Xudong An ◽  
Howard Fultz ◽  
Srinath Iyengar ◽  
Fatemeh Hassanipour
Keyword(s):  
High Speed ◽  
Vortex Flow ◽  
Air Flow ◽  
Vortex Generator ◽  
Ccd Camera ◽  
Injection Velocity ◽  
Custom Made ◽  
Flow Through ◽  
Flow Vortex ◽  
Porous Screen

This study presents the experimental analysis of air flow vortex propagation through porous screens. Our research was conducted with a new and unique experimental setup for measuring and visualizing air vortex flow through porous media. A custom-made, high-precision vortex generator provided a variety of velocity profiles for vortex generation with an unprecedented level of precision. The flow field was captured with the use of a fog generator and a high-speed CCD camera. The porous screens were constructed out of acrylic rods with various orientations, thickness, and porosities from rod separation. The results presented in this paper show the effect of porosity and air injection velocity on the behavior of air flow (separation, accumulation), and the transport phenomena of vortex flow through porous screens.

Aerodynamic Simulation of the Air Flow beneath the High Speed Train

2012 ◽  
Vol 253-255 ◽  
pp. 2035-2040
Author(s):  
Ye Bo Liu ◽  
Zhi Ming Liu
Keyword(s):  
High Speed ◽  
Stokes Equations ◽  
Air Flow ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
Navier Stokes ◽  
High Speed Train ◽  
Navier Stokes Equations ◽  
Pressure Distributions ◽  
High Speed Trains

Numerical simulations were carried out to investigate the air flow and pressure distributions beneath high speed trains, based on the three-dimensional Reynolds-averaged Navier-Stokes equations with the SST k-ω two-equation turbulence model. The simulation scenarios were of the high speed train, the CRH2, running in the open air at four different speeds: 200km/h, 250km/h, 300km/h and 350km/h. The results show that, the highest area of pressure is located at the front underbody part of the train whist the pressure for rest of the train is relatively small. Increasing speed does not visibly increase the pressure coefficient, indicating that the pressure increases with the square of the operational speed.

scholarly journals Numerical Study of Entry Waves Produced by High-Speed Trains Entering a Tunnel. Effects of Nose Shape of Train.

1996 ◽  
Vol 62 (598) ◽  
pp. 2310-2315
Author(s):  
Kazuyuki KAGE ◽  
Toyoyasu OKUBAYASHI ◽  
Takeshi KARIYA ◽  
Shigetoshi KAWAGOE
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
High Speed Trains ◽  
Nose Shape ◽  
Tunnel Effects

scholarly journals Numerical Study of Entry Waves Produced by High-Speed Trains Entering a Tunnel. Effects of Perforated Hood.

1994 ◽  
Vol 60 (578) ◽  
pp. 3402-3407
Author(s):  
Kazuyuki Kage ◽  
Toyoyasu Okubayashi ◽  
Katsutaka Imada ◽  
Shigetoshi Kawagoe
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
High Speed Trains ◽  
Tunnel Effects

scholarly journals Numerical study on aerodynamic characteristics of high-speed trains with considering thermal-flow coupling effects

2017 ◽  
Vol 19 (7) ◽  
pp. 5606-5626 ◽  
Author(s):  
Hong Wei Xing ◽  
Ai Min Yang ◽  
Yi Fan Li ◽  
Ling Zhang ◽  
Li Jing Feng ◽  
...  
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Aerodynamic Characteristics ◽  
Thermal Flow ◽  
Coupling Effects ◽  
Flow Coupling ◽  
High Speed Trains

Numerical study on the slipstream and trackside pressure induced by trains with different longitudinal section lines

2017 ◽  
Vol 232 (6) ◽  
pp. 1671-1685 ◽  
Author(s):  
Taizhong Xie ◽  
Tanghong Liu ◽  
Zhengwei Chen ◽  
Xiaodong Chen ◽  
Wenhui Li
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Longitudinal Section ◽  
Detached Eddy Simulation ◽  
Full Scale Test ◽  
Section Line ◽  
Eddy Simulation ◽  
High Speed Trains ◽  
Scale Test ◽  
Pass Through

Slipstreams are generated when high-speed trains pass through the open air causing safety threat to passengers, trackside workers and infrastructure. This study calculates the slipstream induced by trains with different longitudinal section lines using a detached-eddy simulation. The slipstream velocities and pressure at various lateral distances from the centre of the rail position and various vertical distances from the top of the rail position are calculated at a Reynolds number of 1.8 × 106, and the flow field around the trains is analysed. The results of the calculation are compared with the results of a full-scale test to validate the numerical method adopted in this work. The results demonstrate that the variations in the slipstream velocities induced by the four types of trains are similar as are the variations in the trackside pressures. The amplitudes of the slipstream velocities and trackside pressures are different due to the influence of the longitudinal section line, and both the slipstream velocity and the trackside pressure increase with the slope of the longitudinal section line. The slipstream velocity and trackside pressure decrease with increasing distance from the centre of the rail and the top of the rail. The large difference in the slipstream induced by the four types of trains occurs in regions where the distance from the centre of the rail is greater than 2.5 m and the distance from the top of the rail is greater than 1.5 m, and those regions are also the areas where platform passengers and track infrastructure are located. The results demonstrate that the slipstream in those regions can be reduced by adopting relatively lower slopes of the longitudinal section line.

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