Investigations of rotating stall inception in a propeller turbine runner operating in low-load conditions

Abstract

This paper presents a study of the inception mechanism of a rotating stall instability identified on a model propeller turbine during speed-no-load (SNL) operation. It seeks to understand the origins of columnar vortices dominating the flow in the runner in SNL. It is based on the use of an experimentally validated flow simulation strategy using the SAS turbulence modelling approach. Two sets of boundary conditions were used to identify the onset of the columnar vortices and confirm that they are linked with a boundary layer separation on the turbine head cover.