Studies on LP Turbine Blade Surface Roughness Elements for Controlling Separation Bubble to Improve Aerodynamic Performance of the Turbine Blades

摘要

Demand for highly loaded turbine blades under the low Reynolds number condition has prompted studies on how to avoid, at least minimize, boundary layer separation or separation bubble on the blade suction surface, which otherwise induces the significant aerodynamic loss. This study carries out experimental investigation of aerodynamic effects of surface roughness elements on the suction surface of highly loaded LP turbine blades, where an isolated two-dimensional thin wire is mainly used as the roughness element. The purpose of this study is to see whether such discrete roughness elements, which protrude into the flow through the boundary layer, could have any positive impact on the separation or separation bubble so as to reduce the aerodynamic loss. Quite a few test cases are executed by changing the diameter and/or position of the thin wire. In addition, three-dimensional configurations of short wires are also examined.