Numerical benchmarking of tip vortex breakdown in axial turbines PDF download.
The scope of the current study is to benchmark turbine blade performance in the event of blade passage vortex breakdown with the use of a standard Reynolds-AveragedNavier-Stokes (RANS)computational fluid dynamics (CFD)code.The ultimate goal of the present work is to determine a range of conditions where the CFD does and does notpredict tip vortex breakdown for testing in a turbine cascade rig.It is well known thattip leakage loss has a large impact on the efficiency of turbomachines.There have been numerous studies that have explored minimizing the tip leakage loss with various flowcontrol methods.There have also been many studies to measure tip leakage flow and the resulting tip vortex that is generated in the flowfield.The tip vortex encounters a strong adverse pressure gradient within the blade passage,and on occasion,causes the vortex breakdown.Although there has been much study of vortex breakdown on externalairfoils,there has been relatively limited investigation of tip vortex breakdown in turbomachines.It is unclear if the current design tools are adequate for predicting tipvortex breakdown in axial turbines.