Numerical Study on the Heat Transfer Characteristics of Gas Turbine Vanes Under Active Coolant Control

Active control of the turbine cooling air flow under partial load operation can improve the gas turbine efficiency. To reveal the heat transfer characteristics of turbine vanes during this process, this paper adopts a conjugate heat transfer method. The effect of modulating the cooling air flow is characterized by defining a coolant pressure adjustment coefficient. Combined with design of experiment and response surface models, the variations in vane surface temperature, cooling efficiency, and temperature non-uniformity under different coolant modulation levels are investigated. The results indicate that when the pressure adjustment coefficients of the vane front and rear cavities drop below 0.99 and 0.96, respectively, gas ingestion occurs at the film holes in the corresponding cavities. As the cooling air flow decreases, the high-temperature regions at the vane leading edge, trailing edge, and suction side gradually expand, the cooling efficiency decreased accordingly, and the temperature non-uniformity increased. Empirical formulas for each parameter are obtained through fitting with the response surface model and corrected according to the gas turbine operating conditions. The corrected model shows a maximum relative error of no more than 0.8% on the test data, demonstrating high accuracy and strong generalization performance. This study clarifies the safety boundaries and heat transfer characteristics of active coolant control under partial load operation, providing theoretical support and a data foundation for the design and optimization of active coolant control systems in practical gas turbines.