Control of Tip Clearance Flow of Turbine Cascade With Spherical-Bottom Honeycomb Tip

In this paper, the influence of a new spherical-bottom honeycomb tip structure on the leakage flow of turbine cascade is numerically studied. The influence of the depth of the bottom on the leakage flow is also investigated. The results show that vortices change the structure of the flow field in the honeycomb cavity, and the composite structure with the spherical-bottom honeycomb reinforces this type of vortex, which has a better suppression effect on the leakage flow. Compared with the conventional at tip, the leakage flow of the cascades with honeycomb tip and spherical-bottomed honeycomb tip decreased by 11.18% and 15.13%, and the exit losses decreased by 8.17% and 10.42% respectively. For the spherical-bottom honeycomb tip cascade, both the amount of leakage flow and the loss change parabolically with the geometric depth of the spherical bottom. At the ball depth of 1/6 of the ball diameter, minimum leakage flow and exit loss can be got.