三维横向紊动射流流场结构的数值分析

Numerical Analysis of Three-Dimensional Turbulent Jet in Crossflow

对横向紊动射流流场结构、流动机理的研究具有重要的学术意义,同时对解决工程应用中存在的许多问题具有指导作用。利用RNG模型对横流中单股紊动射流流场的流动特性进行了数值模拟。运用SIMPLEC算法求解了适体坐标系下的控制方程,壁面函数法处理近壁区流动。得到了射流与主气流速度比为2和4的流场。结果表明:较大的射流速度对主气流流场影响大;射流内部已形成明显的反向涡旋对(CVP);射流喷孔上游处出现了主气流向喷孔内部流动的趋势;射流喷孔背风侧存在尾迹区。

A turbulent jet issuing transversely into a uniform crossflow is an important type of fluid flow and can be found in many engineering applications. It is of both academic and applied value to research its structural features and flow mechanisms. The characteristics of the turbulent jet-to-crossflow have been given through numerical simulation. The SIMPLEC algorithm in the body-fitted coordinates and wall-function method using the RNG k-ε turbulence model are adopted to simulate this flow at two jet-crossflow velocity ratios,2 and 4. The mean velocity and the turbulent kinetic energy computed from the simulations match experimental measurements well, and the larger jet-crossflow velocity ratio can change the flow fields more obviously. The counter-rotating vortex pair (CVP) is an important phenomenon of the jet, and it is found in the vortical results. There are separation events in the lee of the jet and the mechanism is analyzed.Figs 7, table 1 and refs 10.