Numerical investigation on the biomimetic trailing edge of a high-subsonic turbine blade

Abstract

In this study, the structure of a harbor seal vibrissa, or whisker, is applied to the trailing edge of a high subsonic turbine blade to reduce wake loss. A method of generating biomimetic geometry is provided. In order to study the mechanism of wake loss reduction for the biomimetic trailing edge, four trailing edge shapes are studied numerically: with circular (prototype blade), elliptic, sinusoidal and biomimetic. The delayed detached-eddy simulation (DDES) approach is used to predict the flow details around the blades. Results show that a substantial reduction of mixing loss is obtained for the blade with a biomimetic trailing edge. The coherent structures of Karman vortices are completely suppressed and transformed into smaller vortices with distinct three-dimensional characteristics owing to the influence of biomimetic trailing edge. Such small vortices dissipate quickly during the mixing with the mainstream, so the wake area for biomimetic trailing edge case is much narrower, and the velocity in the wake recovers more quickly compared with the situation in the other three cases. The vortices shedding from the suction side and pressure side move from the geometric peaks to the valleys when moving downstream.