A Combined Numerical and Experimental Study of the Effect of Non-Axisymmetric Contouring on Performance and Film Cooling Behavior of a Rotating Turbine Endwall

Applying a new non-axisymmetric endwall contouring technology introduced by Turbomachinery Performance and Flow Research Laboratory (TPFL) at Texas A&M University to the second rotor row of a three-stage research turbine, has shown that for a single rotor row a major turbine efficiency improvement can be achieved [1]. Motivated by these results, comprehensive numerical and experimental investigations on the TPFL research turbine were conducted to determine the impact of the endwall contouring on film cooling effectiveness. For this investigation, the first rotor row directly subjected to the purge flow injection was chosen to which the new contouring technology was applied. Performing an extensive RANS simulation by using the boundary conditions from the experiments, aerodynamics, performance and film cooling effectiveness studies were performed by varying the injection blowing ratio and turbine rotational speed. Performance measurements were carried out within a rotational speed range of 1800 to 3000 RPM. The corresponding CFD simulations were carried out for four rotational speeds, 2000, 2400, 2600, and 3000 rpm. Comparison of the RANS aerodynamics simulation with experiments reveals noticeable differences. Considering the film cooling effectiveness, major differences between experiment and numerical results were observed and discussed in the paper.