壁面局部振动的二维管内流动分析

通过求解二维雷诺时均Navier-Stokes方程,对壁面局部振动的二维管内流场进行数值模拟,分析边界条件在不可压缩计算及可压缩计算情况下对壁面局部振动流动状态的不同影响.研究表明,在不可压缩计算情况下,总压入口条件相对于速度、质量流量入口条件限制少,壁面振动可同时影响振动壁面上、下游的流动参数.在壁面振动管道内,尽管马赫数Ma0.3,可压缩流体的流动现象是完全不同于不可压缩流体的.边界条件对于高频振动计算结果的影响比低频振动计算结果的小.因此,在模拟燃气轮机小幅高频振动叶栅的实际工程问题中,必须采用可压缩计算.在相对平缓、充分的入口段条件下,仍然可以采用常规模拟叶片绕流时的速度入口边界条件进行计算.

Two-Dimensional Flow Analysis of Locally Vibrating Wall Tube

By solving the two dimensional RANS Navier-Stokes equations,the partially vibrating wall in the two-dimensional tube flow field was simulated and the impact of different boundary conditions in the calculation of incompressible and compressible situations on the partially vibrating wall was analysed.The results show that:compared with the total pressure inlet condition,the velocity inlet and mass flow inlet conditions have less restriction on the flow in the case of incompressible calculation,so,the wall vibration can affect the up and down stream flow parameters simultancously.Moreover,even if the Mach number Ma<0.3,the compressible fluid flow phenomena are completely different from those under the incompressible fluid calculation conditions.Meanwhile,compared with low-frequency vibration conditions,the influence of boundary conditions on the calculation results of high-frequency vibrations is even smaller.Therefore,to simulate the actual gas turbine with a small high-frequency vibrating cascade,in the calculation the compressibility of fluid should be taken into account.Under relatively gentle and sufficient inlet conditions,a conventional analogic velocity inlet in the calculation of the flow around the blade can still be used.