基于粒子轨迹的结冰风洞收缩段优化设计数值模拟

为了研究收缩段型面和液滴轨迹特性对结冰风洞流场品质与结冰试验效果的重要影响,获得收缩段的优化设计参数,采用数值模拟方法,使用二维简化模型对3m×2m结冰风洞收缩段的流场特性进行了研究,对几种典型收缩曲线的流场进行了计算,对比了收缩曲线对沿轴向压力分布、出口截面速度分布、不同粒径云雾粒子的极限释放距离及试验段入口云雾粒子分布的影响,结果表明:三次曲线与x_m为0.4的五次曲线不能满足流场合格指标,其他曲线流场特性差别不大,维氏曲线具有最小极限释放距离,在收缩段出口,三次曲线和五次曲线粒子包络面积最大,综合比较,x_m为0.5的五次曲线能有效兼顾流场均匀性、极限释放距离和收缩段出口粒子包络面积比.

Numerical sumulation on optimization design of contraction section in icing wind tunnel based on droplet trajectory

Performance of icing wind tunnel's contraction section was investigated by numerical simulation.For several typical wall contours were provided by former researchers,the flow field calculation using simplified 2-D (two-dimensional)model was performed,and the pressures along the centerline and the velocity distribution at the test section entrance were obtained.The numerical simulation results show that all contraction curves can prevent the separation of boundary layers,and the difference of fluid dynamics parameters is negligible except for cubic curve and fifth power curve(x_m=0.4) which can't provide a specified degree of uniformity.Then droplet trajectory was studied by numerical simulation when different diameter water-liquid that the droplets were released.The numerical results state droplet accretion using Witozinsky curve is less compared with that designed by other curves.By comparing of several contraction curves' effect on flow field and droplet trajectory,it can be concluded that convergent section designed by fifth power curve (x_m=0.5) has higher efficiency.