Effects of Coolant Injection Configuration on the Cooling Performance of Gas Turbine Stage Using CFD and Conjugate Heat Transfer Method

Abstract

The effects of coolant injection configuration on the cooling performance in the wheel space cavity and rotating components of gas turbine stage and the aerodynamic performance influenced by the interaction between rim seal purge flow and main flow of the stage were numerically investigated using CFD and conjugate heat transfer method. Three-dimensional Reynolds-Averaged Navier-Stokes (RANS) and SST turbulent model were utilized to analyze the flow and heat transfer characteristics of gas turbine stage model with vane, blade and inter wheel space cavity. Fluid domain including stator and rotor blade passage, wheel space cavity as well as rim seal and solid domain including solid blade and rotating disk were considered in the present computational domains. Center coolant injection, center coolant injection combined with high position pre-swirl coolant injection, and high position pre-swirl coolant injection configuration for the axial rim seal were used to investigate their influence on the cooling effectiveness and aerodynamic performance of the turbine stage. In addition, the influence of rim seal configuration with center coolant injection on the cooling effectiveness and aerodynamic performance of the computational domains is also investigated. Numerical results show that the coolant injection configuration influences both the cooling effectiveness and flow field in the wheel space cavity and the aerodynamic performance of the turbine stage. The rim seal configuration mainly influences the cooling effectiveness in the wheel space cavity but its effect on aerodynamic performance is ignorable in this work. The internal flow and heat transfer behavior of stage passage and wheel space cavity, as well as the cooling effectiveness of the rotor blade and rotating disk were also illustrated and discussed.