采用数值计算和结冰风洞实验相结合的手段,对某运输机机翼剖面缩比翼型的结冰特性进行了研究.结冰实验在气动中心0.3m×0.2m结冰风洞中进行,实验模型为弦长0.18m的层流翼型.翼型的绕流流场通过求解低速黏流的时均Navier-Stokes(N-S)方程得到,采用拉格朗日法计算水滴撞击特性,在此基础上,求解结冰热力学模型,获得结冰外形.对计算和实验结果进行了对比分析,发现虽然局部冰形轮廓还存在差异,但计算和实验得到的冰形在结冰极限、冰形体积和主要特征等方面基本一致.研究显示:在结冰的初始阶段,翼型前缘的冰形较规则,随着结冰时间的增加,冰形逐渐变得不规则;翼型下表面冰体前部为明冰,冰体后部、尤其是结冰极限附近则呈现典型的霜冰特征;翼型上表面的结冰范围远小于下表面,在结冰极限附近也不再有明显的霜冰.
Ice accretion characteristics on the airfoil of a transport aircraft were studied with both experimental and computational methods.Icing test was carried out in the icing wind tunnel of 0.3 m×0.2 m test section,in China Aerodynamics Research and Development Center.The test model is a 0.18-m-chord laminar airfoil,which is the sub-scale model of the transport aircraft's wing section.Numerical simulation of icing was based on computational fluid dynamics(CFD) method.The flow field of airfoil was calculated by solving time averaged Navier-Stokes equations.Droplet trajectories and impingement characteristics were computed with a Lagrangian method.Ice shape was then obtained after solving the thermodynamic model of icing.Computational results were compared with experimental results.Despite of some geometric differences,the volume,limit and main characteristics of computational ice shape agree well with the experimental results.The study shows that the ice shape on the leading edge of airfoil is streamline at the initial stage of icing,and becomes irregular with increase of icing time.At lower surface of the airfoil,foreside ice is made up of glaze ice,while rear ice,especially ice near the lower impingement limit,is made up of rime ice.At upper surface of the airfoil,icing region is much smaller than that at lower surface,and there is no obvious rime ice even near the upper impingement limit.