Numerical investigation for effect of non-axisymmetric endwall profiling on secondary flow in turbine cascade

Numerical simulation has been carried out to obtain detailed flow structure in conventional turbine cascade and two kinds of turbine cascade with non-axisymmetric endwall. Comparison and analysis of development process of passage vortex in three kinds of turbine cascade have been performed to find out how non-axisymmetric endwall profiling affect secondary flow in turbine cascade. Investigation result shows: When lower endwall of turbine cascade protrudes upward, total pressure loss at exit of cascade decreases 4.2% than conventional turbine cascade; When lower endwall of turbine cascade protrudes downward, total pressure loss at exit of cascade increases 11.9% than conventional turbine cascade. When lower endwall of turbine cascade protrudes upward, compared with conventional cascade and cascade with lower endwall protruded downward, formation of lower passage vortex is 'later' , so less 'opportunity' is acquired to grow fully. This is the key point which makes non-axisymmetric endwall profiling work effectively.