Research On Optimization Design Of High Temperature Turbine Blade Cooling Structure

Increasing the inlet temperature of the gas turbine is one of the important ways to improve the performance of the gas turbine.In order to make the turbine blades work stably in a high temperature environment,the cooling structure of the turbine blades must be optimized accordingly.The traditional manual optimization of the cooling structure of turbine blades is time-consuming and labor-intensive,and the optimization results obtained have a certain discreteness,and the optimal results may not always be found.With the continuous deepening of the optimization theory and the continuous improvement of the optimization algorithm,it has become a trend of optimization design to use the optimization design platform to optimize the optimization.Based on the above practical engineering background,this paper studies and builds an optimization design platform for turbine cooling structure.The platform includes parametric modeling of turbine cooling structure,automatic generation of computational domain grid,automatic CFD calculation and post-processing,and automatic optimization process under certain optimization strategies.Using the optimization platform,the optimization design idea of "from front to back,complementary advantages,separation of inside and outside,adiabatic optimization,and coupling verification" is adopted to optimize the design of the external air film cooling structure and the internal cross-rib cooling structure.For the optimization of external air film cooling,compared with the original model,the average cooling efficiency of the leading edge of the blade after optimization is increased by 25.5%,the average cooling efficiency of the pressure surface is increased by 2.89%,and the average cooling efficiency of the suction surface is increased by 0.15%.According to the design idea,the internal cross-rib cooling structure is divided into four different areas: front,middle,rear,and tail.The cross-rib structure is optimized.After optimization,compared with the original model,the comprehensive heat transfer factor(TPF)of the front,middle,rear and rear cross ribs increased by 24.68%,0.41%,0.39% and 3.49%,respectively.At the same time,the joint calculation analysis of different cross-rib areas after optimization is carried out.Under the same inlet flow conditions,the comprehensive heat transfer factor(TPF)of the optimized model is increased by 10.45%;Thermal Factor(TPF)has been improved by 2.87%,while inlet cold air flow has been reduced by 12%.The original model and the optimized model were calculated by gas-heat coupling respectively,and the cold air flow in the front cavity and the rear cavity of the optimized structure was reduced by 10% respectively to verify the feasibility of the optimized platform.From the air-heat coupling verification results,compared with the original model,under the condition of unreduced cooling air flow,the average temperatures of the leading edge,pressure surface and the entire blade of the optimized blade decreased by 9 K,7 K and 3 K,respectively.The average temperature of the suction side has risen by about 5 K.The cold air flow in the front cavity of the optimized model was reduced by 10%.Compared with the original model,the average temperature of the leading edge and the pressure surface of the optimized model decreased by 8 K and 2 K respectively,the average temperature of the suction surface increased by 4 K,and the temperature of the entire blade was basically remaining unchanged;reducing the cold air flow in the rear cavity of the optimized model by10%,compared with the original model,the average temperature of the leading edge and the pressure surface decreased by 11 K and 4 K respectively,the average temperature of the suction surface increased by 6 K,and the entire blade The average temperature has risen by around 2 K.