Effect of rim seal purge flow on performance and thermal loading of turbine

The effect of rim seal purge flow on flow field, performance and thermal loading for a two-stage turbine was studied by utilizing conjugate heat transfer. It was found that under the effect of purge flow and main flow interaction, a nonlinear relationship between cooling effect and coolant flow rate was observed. In this case, utilizing the conjugate heat transfer could observe the dramatical change in the temperature field and aerodynamic losses simultaneously. Moreover, the operation point shifted along performance map due to the blockage effect of coolant flow in the adjacent stage, a 2.5% coolant flow rate could result in a 0.6% variation of main flow rate and a 1.2% reduction of expansion ratio for upstream turbine stage. In the main passage, the coolant flow could reduce the aerodynamic loading at the root forming the viscous shear layer, and significantly modify the secondary vortex, eventually resulting in performance penalty.