Numerical study on optimal structural parameters of train wind barrier based on orthogonal design

基于正交设计的列车风屏障结构参数优化的数值研究

Wind barriers have attracted significant attention as an effective measure to ensure train safety under crosswinds.However,in past decades,the influence of structural parameters such as the height and ventilation ratio of wind barriers on the difference of the average pressure coefficient between the train windward and leeward surface(ΔCp)has not been fully investigated.To determine the influence of the interaction among the three factors,namely the wind barrier height(H),ventilation ratio(R),and distance to the train(D),twenty five numerical simulation cases with different structural parameters were considered based on an orthogonal design.The shear stress transfer(SST)k-ωturbulent model was employed to calculate the wind pressure coefficients,and the calculation accuracy was validated by using wind tunnel experiments.The results indicated that with an increase in R,ΔCp first decreased and then increased,andΔCp decreased while D increased.Moreover,with the increase in H,ΔCp first increased and then decreased.Therefore,these three factors must be considered during the installation of wind barriers.Furthermore,according to a range analysis(judging the relative importance of the three factors intuitively),the three factors were ranked in the following order:R>H>D.Based on a variance analysis,R was found to be of high significance toΔCp,followed by H,which was significant,whereas D had relatively insignificant influence.Finally,the optimal values of R and H were determined to be 20%and 110 mm,respectively.And when R=40%,H=85 mm,the train was relatively unsafe under these such conditions.The findings of this study provide significant guidance for the structural design of wind barriers.

风屏障由于能提高侧风下列车的行车安全性,近年来引起了学者的广泛关注。然而,在过去的几十年中,风屏障结构参数(如风屏障高度和透风率等)对列车迎风面和背风面的平均压力系数差的影响研究尚不充分。为综合考虑风屏障高度、透风率以及风屏障与列车间距对列车平均压力系数差的影响,本文基于正交设计方法,对25个不同结构参数工况进行了详细数值模拟研究,并采用同步风洞试验验证了结果的正确性。研究结果表明:随着透风率(R)的增加,列车平均压力系数差先减小后增大;随着高度(H)的增加,列车平均压力系数差先增加后减少;而随着风屏障与列车间距(D)的增大,列车平均压力系数差则呈单调减小趋势。此外,根据极差与方差分析理论发现,三个因素的相对重要性为:透风率>高度>风屏障与列车间距。最后,确定了建议风屏障透风率和高度,分别为20%和110 mm。而当透风率为40%,高度为85 mm时,列车处于相对不安全的状态。研究成果可为风屏障的结构设计提供参考。