A Numerical Analysis on Effects of Boundary Layer Fence on Blade Passage Aerodynamics and Loss Reduction

Abstract

Mitigation of total pressure loss and improvement in aerodynamic performance are obtained on a low aspect ratio turbine blade. The turbine blade hub region is constructed with a boundary layer fence to reduce secondary losses. The major objective of implementing boundary layer fence is to restrict the pressure side leg of horseshoe vortex from reaching suction surface of adjacent blade. This decreases the loss associated with the passage vortex by delaying its development. Present analysis reveals the aerodynamic performance of boundary layer fence in three ways. Firstly a rectangular strip is kept close to the suction surface in order to break the suction side leg of horseshoe vortex. Secondly, to restrict the pressure side leg of horseshoe vortex from traversing from pressure surface to suction surface a fence of curved trailing edge is kept at the middle of the blade passage. In the third configuration the combined effects of both rectangular strip and fence have been analyzed. In this work the shape of the rectangular strip and fence do not follow the blade profile. Ansys-cfx, commercial software is used for numerical analysis. The results indicate that the presence of strip has resulted in the breakdown of suction side leg of horseshoe vortex and the location of fence has directed the pressure side leg of horseshoe vortex more axially rather than traversing across the blade passage. The combination of both geometries has achieved further reduction of total pressure loss coefficient. © 2024 American Institute of Physics Inc.. All rights reserved.