2017 Volume 12 Issue 2 Pages JTST0025
A comparative investigation of leakage flow and film-cooling characteristics on different squealer tips is conducted under the conditions of stationary and moving casing. Firstly, the numerical method used in the calculations has been verified. Then, the influences of film-hole arrangement, squealer height and blowing ratio are studied in detail. Three different film-hole configurations are taken into consideration. For type-A and type-B, the film holes are arranged in one row, but located on the middle-camber line and near the suction side squealer, respectively. Type-C places two rows of 7 film holes at the leading edge and one row of 6 film holes at the middle chord region. The results show that the relative motion of the casing leads to the formation of a scraping vortex near the casing, which not only compresses the cavity vortex, but also acts as a pair of labyrinths with the cavity vortex to the leakage flow. The effect of the moving casing on the film-cooling effectiveness of squealer tip varies with the film-hole arrangements. When the casing is moving, the tip leakage loss increases with the decrease of the rim height because the blockage effect of the vortexes in the cavity decreases. Nevertheless, type-C obtains the best tip cooling performance in both cases of stationary and moving casing.
