二维翼型大尺寸过冷水滴撞击特性及冰形分析

基于现有大尺寸过冷水滴(supercooled large droplet,SLD)动力学特性,分析水滴变形对阻力的影响.并根据几种典型的反弹/飞溅模型,分析了SLD的阻力变化、反弹、飞溅等对水滴撞击特性的影响,采用软件FENSAP-ICE的飞溅模型和LEWICE 2.0的反弹模型研究了反弹及飞溅现象对冰形的影响.计算结果显示:水滴撞击前的破碎现象对水滴尺寸分布有较大的影响,进行撞击特性以及冰形计算的时候需进行考虑;SLD破碎、飞溅、反弹降低了局部水收集系数、减小了水滴撞击范围;飞溅现象主要发生在机翼前缘附近区域,反弹主要在撞击边缘区域;水滴直径增加,飞溅现象逐渐减弱,但边缘位置的反弹现象一直很明显.SLD变形带来的阻力影响对冰形及结冰区域影响很小;与未考虑飞溅及反弹现象得到的冰形比较,考虑飞溅及反弹得到冰形前缘区域形状变化不大,但是整体结冰区域减小.

Analysis on supercooled large droplet impingement characteristics and ice shape of two-dimensional airfoils

Based on existing supercooled large droplet (SLD) dynamic characteristics, the effects of droplet deformation on drag were analyzed, and the effects of drag change, rebounding and splashing of SLD on droplet impingement characteristics were analyzed by several typical rebounding/splashing models. The splashing model from software of FENSAP-ICE and rebounding model from software of LEWICE 2.0 were used to study the influence of rebounding and splashing to ice shape. The results show that the droplet diameter distribution is influenced greatly by the breaking up before droplet impingement, which should be considered in calculation of impingement characteristics and ice shape; breaking up, splashing and rebounding of SLD results in the decrease of local water collection coefficient and droplet impingement region; the splashing occurs mainly near the leading edge of airfoils and rebounding occur near the edge of the impingement region; with the droplet size increasing, splashing becomes weak, while rebounding is still obvious; the effect of drag change induced by SLD deformation on ice shape and ice accretion region is negligible; compared with the ice shape without considering splashing and rebounding, the ice shape considering splashing and rebounding is approximately the same at the leading edge, while the whole ice accretion region is smaller.