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采用CFD方法,对带进气回流的离心压气机进行了仿真研究,并根据试验进行了验证。为了拓宽离心压气机的稳定工作范围,根据原型机流场,改变了回流槽的几何,仿真结果表明改型能有效拓宽离心压气机的运行范围,且不明显改变压气机效率和压比.流场分析表明,改型增添的导流段对气流的导流作用引起回流槽前槽出口气流方向变化后,叶轮靠近叶顶部位轴向速度增大,叶轮前缘相对气流角降低,叶轮槽道靠近叶顶部位子午速度增加,槽道堵塞情况减轻,流动更为顺畅,是改型拓稳的原因。在80 kr·min~(-1)下,回流量增大,引起后槽下游轴向逆流区域扩张,叶轮吸力面分离流动加剧,是拓稳轻微失效的原因.改型机和原型机几何形状差异小,属于一种简易而有效的拓稳方案。
The CFD method is used to simulate the centrifugal compressor with intake backflow and verify it according to the test. In order to widen the stable working range of centrifugal compressor, the geometry of the return channel is changed according to the prototype flow field. The simulation results show that the modification can effectively expand the operating range of the centrifugal compressor without significantly changing the compressor efficiency and pressure ratio. Field analysis shows that after the diversion of the modified diversion duct to the airflow causes the airflow direction at the outlet of the back groove to change, the axial velocity of the impeller near the top of the blade increases, the relative airflow angle at the front of the impeller decreases, Near the top of the leaf, the meridian speed increases, the channel blockage is alleviated and the flow is smoother, which is the reason for the modified stability. At 80 kr · min ~ (-1), the backflow increases, causing the axial countercurrent zone to expand downstream and the impeller suction surface to separate and flow more aggravating, which is the reason for the slight failure of stability improvement. The difference is small, belongs to a simple and effective top-stability program.