涡旋压缩机非定常流动的三维数值模拟

Numerical Simulation of Three-dimensional Unsteady Flow in the Scroll Compressor

针对涡旋压缩机工作过程中运动部件公转平动的运动方式使得工作腔内流场难以测试的问题,提出了带有移动边界、啮合间隙和封闭工作腔的涡旋压缩机非定常流动的三维数值计算方法。以齿头双圆弧修正型线为例,建立了三维几何模型。解决了带有啮合点的动边界在动网格中容易出现的负体积问题以及排气口遮挡问题,实现了三维数值模拟。得到了任意曲轴转角下的各工作腔内各截面的气体流动的压力和速度的动态分布规律,揭示了增压过程中腔内流动状态的变化机理。模拟结果表明:压力在各工作腔分布均匀,最大与最小压力之差不超过5%。沿着涡旋齿型线齿尾到齿头,内外侧的压差逐渐增大。速度分布不均匀,单个工作腔内最大最小速度之差可达到180m/s。径向泄漏沿啮合线呈对称分布,速度呈跳跃式分布,最大泄漏速度为200m/s,切向泄漏最大泄漏速度可达450m/s。

To solve the problem that the flow field in the working chamber of the scroll compressor can not be get in experimental way,because of the translational revolve pattern of its movement part,a three dimensional unsteady numerical method with a moving boundary,clearance and closed chamber was supposed. The geometric model was obtained based on the profile with double arc correction. The problem that the negative volume in a moving boundary was solved and the three dimensional numerical simulation was achieved. The pressure and velocity fields on each section under any crank angle were obtained,so it can show the change of the flow state directly and reveal the change mechanism in the pressurization. The simulation results show that,the pressure field in working chamber was well-distributed,the difference between the maximum and minimum pressure does not exceed5%. The differential pressure gradually increased along the profile. Velocity distribution is uneven,in a single working chamber the difference between maximum minimum speed can reach 180 m / s. Radial leakage along the meshing line are symmetrical distribution,and the maximum of the leakage velocity can reach 200 m / s,the maximum of tangential leakage velocity was up to 450 m / s.