Effect of stepped squealer tip on <bold>f</bold>low of <bold>l</bold>eakage <bold>t</bold>hrough <bold>t</bold>urbine <bold>b</bold>lade <bold>t</bold>ip

Abstract

<p indent="0mm">Flow of leakage through the clearance of a turbine blade tip is an important factor that affects turbine loss. Setting up proper geometrical structures for the blade tip is an effective method for realizing passive control of leakage flow and suppressing loss due to leakage. Among these structures, squealer tip is a simple and widely studied control structure|and with focus on elucidating its vortex system structure and suppression mechanism, this study proposes a new stepped squealer blade tip structure by modifying that of a conventional one in order to further improve its control effect on the flow of leakage. Influences of different squealer tips on the control of the flow of leakage are discussed in detail. Results show that the modified squealer tip can effectively alter the flow of leakage and suppress loss due to leakage. With increase in the depth of the squealer tip, the strength of vortex structures in the groove increases and the flow of leakage through the tip decreases. With respect to the same depth of squealer tip, the back-stepped squealer tip exhibits better suppression effect on the flow of leakage than the front-stepped squealer tip along the direction of the flow of leakage. The front-stepped squealer tip is not effective for controlling the flow of leakage.