﻿ 低真空管道磁浮列车气动特性 Aerodynamic Characteristics of Maglev Train on Low Evacuated Tube

International Journal of Mechanics Research
Vol. 08  No. 02 ( 2019 ), Article ID: 30697 , 9 pages
10.12677/IJM.2019.82013

Aerodynamic Characteristics of Maglev Train on Low Evacuated Tube

Dawei Chen1, Dilong Guo2*

1National Engineering Research Center, CRRC Qingdao Sifang Co., Ltd., Qingdao Shandong

2Key Laboratory for Mechanics in Fluid Solid Coupling Systems, Institute of Mechanics, Chinese Academy of Science, Beijing

Received: May 16th, 2019; accepted: Jun. 4th, 2019; published: Jun. 11th, 2019

ABSTRACT

Based on compressible Naiver-Stokes equation, the aerodynamic characteristics of maglev train on different tube area and pressure are studied. The results indicated the flow field around maglev train in low evacuated tube is similar to that in open air, the annular space between maglev train and tube is similar to Laval nozzle and has the flow characteristics of expansion acceleration or compression deceleration, when the speed of maglev train reaches the critical speed, there will be shock wave at the rear of maglev train, the aerodynamic forces of maglev train increase with the decrease of tube area, the aerodynamic forces of the tail car will increase dramatically when the shock wave occurs at the tail of maglev train. The aerodynamic coefficients of maglev train decreases slightly with the increase of tube pressure, but tube pressure changes, resulting in Reynolds number changes, so as to the aerodynamic coefficients of maglev train are quite different.

Keywords:Low Evacuated Tube, Maglev Vehicle, Blockage Ratio, Tube Pressure, Aerodynamic Characteristics

1中车青岛四方机车车辆股份有限公司，国家工程研究中心，山东 青岛

2中国科学院力学研究所，流固耦合系统力学重点实验室学院，北京

1. 引言

2. 计算模型和网格

2.1. 计算模型

Figure 1. The schematic diagram of computational model

2.2. 计算域与计算网格

Figure 2. The computational domain

Figure 3. The local computational mesh

3. 计算方法

$Kn=\frac{\lambda }{L}$ (1)

$\lambda =\frac{{k}_{B}T}{\sqrt{2}\text{π}{d}^{2}p}$ (2)

$Kn=\frac{{\lambda }_{\mathrm{max}}}{L}=1.5×{10}^{-6}\ll 0.01$ (3)

4. 计算结果及分析

4.1. 低真空管道列车扰流的流场特性

Figure 4. The train head pressure contours and the longitudinal profile streamlines

Figure 5. Velocity contours on symmetry plane

Figure 6. Pressure contours on the train tail and the velocity contours on symmetry plane

Figure 7. Streamlines in the tail flow field

Figure 8. Mach contours on symmetry plane

4.2. 管道面积对于列车气动特性的影响

${C}_{D}=\frac{{F}_{x}}{0.5{\rho }_{\infty }A{v}_{\infty }^{2}}$ (4)

${C}_{L}=\frac{{F}_{z}}{0.5{\rho }_{\infty }A{v}_{\infty }^{2}}$ (5)

Figure 9. Coefficients of drag on tube area at different speed

Figure 10. Coefficients of lift on tube area at different speed

Figure 11. Mach contours on symmetry plane

4.3. 管道压力对于列车气动特性的影响

Figure 12. Coefficients of drag on tube pressure at different speed

Figure 13. Coefficients of lift on tube pressure at different speed

5. 结论

1) 低速运行时，低真空环境下磁浮列车与明线磁浮列车的流场特性相似。列车与管道组成的环状空间形成了拉瓦尔喷管效应，磁浮列车到达临界速度时，列车尾部会出现激波，管道面积不同时，管道中出现激波的磁浮列车临界速度不同。

2) 列车的气动力随着管道面积的减小而增大，列车尾部出现激波后，尾车的气动力会激剧增大。

3) 列车的气动力系数随着管道压力的增加下降，但管道压力变化大时，导致雷诺数变化大，从而列车的气动力系数有较大不同。

Aerodynamic Characteristics of Maglev Train on Low Evacuated Tube[J]. 力学研究, 2019, 08(02): 109-117. https://doi.org/10.12677/IJM.2019.82013

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14. NOTES

*通讯作者。