为研究不同宽度叶顶间隙对亚音速半开式离心叶轮性能与内部流场的影响，对某工业用半开式离心叶轮选用不同形式和几何参数的叶顶间隙，通过数值模拟得出结论：随叶顶间隙宽度减小，叶顶附近湍动能减少，离心叶轮通道压比和效率更高，但是失速裕度也变小；在本研究范围内，综合考虑性能和失速裕度，叶顶间隙宽度为0.4 mm时最优；叶顶间隙宽度对泄漏流和主流相互作用有一定影响；随叶顶间隙宽度减少，叶顶间隙泄漏流量减少，本文的分析结果为离心压缩机的工业设计提供了一定参考。

To determine the impact of tip clearance of different width on the performance and internal fluid flow of subsonic unshrouded centrifugal impeller,different tip clearance with various geometry parameter was numerically studied for an unshrouded centrifugal impeller. It was concluded that reducing tip clearance width results in decrease in turbulence kinetic energy,and the performance of centrifugal impeller passage would be better,but the stall margin is also reduced. In the scope of this article,concerning the performance as well as the stall margin,tip clearance of 0.4 mm is the optimum choice.The width of tip clearance has impact on the interaction between the main flow and the leakage flow. By reducing tip clearance,the mass flow rate of tip leakage flow is reduced. This study can serve as a reference on industrial design of centrifugal impeller.

TK474.8+2

国家自然科学基金资助项目（51276108）