轮胎滚动溅水与垂直入水相似性分析

Similarity of spray generated by tire rolling in the water and falling into water

飞机在积水跑道上滑跑时,轮胎溅起的水可能进入发动机,导致发动机出现掉转、喘振甚至熄火等现象.以往对机轮溅水问题的研究主要采用全机溅水试验的方法,这样的试验价格昂贵,且得到的有效数据有限.首先,通过对轮胎溅水机理的分析,根据流动相似理论以及切片法思想,阐述了轮胎滚动溅水与垂直入水的相似性.然后,使用LS-DYNA商业软件分别建立了基于SPH-FEM耦合方法的弹性带翻边轮胎滚动溅水与垂直入水模型,根据数值计算结果分析了两系统中侧向喷溅的形成机理,并对比了两种侧向喷溅的正视溅水形态、溅水速度以及翻边的作用效果.结果表明,当两系统中轮胎速度存在一定对应关系时,两种侧向喷溅的正视形态存在相似性.最后,根据这种相似性提出了采用轮胎垂直入水试验研究机轮溅水形态的新方法,为该问题的研究提供了新的思路.

The spray produced by aircraft tire running on wet runway may enter the inlet of engines, and lead to the compressor stall, surge, or even combuster flameout. Scholars used to study this problem by full-scale aircraft spray test, which may cost a lot, and get only a little valid data. According to the analysis of the interaction between tire and water, the similarities of the spray generation and propagation by tire rolling in the water and tire falling into water are proposed based on combining the strip method with the fluid similarity theory. Then the numerical models of an elastic chined tire rolling in the water and falling into water are established by coupled smoothed particle hydrodynamics（SPH） and finite element method（FEM） in LS-DYNA software. According to the numerical results, the mechanism of the side plume is given. The front views of the side plume in these two spray systems are compared to certify the similarity. At last, the test of tire falling into water is recommended to investigate the basic phenomenon of aircraft tire spray based on this kind of similarity.