多孔介质方法对铁路沿线沙障模拟的适用性分析

为模拟细孔透隙式铁路沙障的流场特征,鉴于此类模拟建模的困难性,采用CFD数值模拟程序,基于三维模拟的多孔介质条件对阻沙固沙网和防风沙直立栅栏的流场特征及压力变化进行模拟分析。通过边界条件和参数的合理控制得到:直立栅栏流场的数值模拟结果与风洞实验下的流场速度变化相似;由于栅栏的整流作用,在多孔介质模拟方法下沙障后出现明显的减速恢复区,并在其后逐渐恢复为与入口相同的风速廓线流;结合全断面PE网风洞试验,采用多孔介质模型可以得到与试验数据相吻合的模拟结果,且压降随入口速度的增加明显增大;由模拟结果可知,通过参数的合理控制,多孔介质方法可较好地反映此类沙障的流场变化。

Simulation Applicability Analysis of Sand-protecting Barrier along the Railway Based on Porous Media Method

To simulate the flow field characteristics of multiaperture sand-protecting barrier along the railway with a view to the difficulties in such simulation modeling,the essay uses CFD numerical simulation program to analyze the flow field characteristics and pressure changes of the polythene net and the upright sand-preventing fence based on the 3D simulation of the porous medium condition. With reasonable control of the boundary conditions and parameters,the results show that( 1) the numerical simulation of the upright sand-preventing fence is similar to the rate of flow field in wind tunnel experiment,slow recovery area appears obviously after the barrier in porous media simulation because of the effect of rectification of the fence and returns to the same wind speed profile flow at the entrance;( 2)combined with the whole section polythene net wind tunnel test,the same simulation results as the test data are obtained by porous media model and the voltage drop increases obviously with the increase of the inlet velocity. The simulation results show that porous media method can better reflect the changes of the flow field of such barrier with proper control of parameters