基于NURBS理论的列车曲面优化方法

在CATIA软件环境中应用NURBS理论完成对CRH1A型动车组三维曲面的建模,使用ICEM CFD软件生成网格,再使用FLUENT软件对其外部流场进行数值计算,分析CRH1A型动车组气动特性后,发现其驾驶室由于曲率过大等因素引起的阻力大、尾流紊乱程度大等问题,因此采用传统的建模方法重新设计列车流线型外形并进行相应的气动特性计算与分析。对照后得出两者的空气阻力头尾车受到的空气阻力所占比例最大,整列列车空气总阻力主要表现为空气压差阻力,重新设计后的列车空气阻力相比CRH1A减小了12.16%。最后比较分析了两种建模方法各自的优缺点,并且提出了根据模型曲面复杂程度选择建模方法的一般性原则。

Optimization Method of Train Surface Based on NURBS Theory

NURBS theory is applied to complete the 3D curved surface modeling of CRH1A EMUs in CATIA software environment and grid is generated in ICEM CFD software, then numerical calculation is given in FLUENT software. After analyzing the aerodynamic characteristics of CRHIA, problems such as the too large air resistance of cab and the large degree of wake turbulence caused by high curvature of cab are found. So the streamline train is designed by traditional modeling methods and gets the aerodynamic characteristics analysis. After two model collated, major conclusion is found that head car and tail car have the largest proportion of air resistance, and train air resistance mainly performance for the air pressure resistance, the resistance of air after redesigned train compared to CRH1A is reduced by 12.16~. Finally, this paper analyzes and compares advantages and disadvantages of the two modeling methods, and puts forward the general principles of selecting modeling method according to surface model complexity.