Research On Optimization Design Technology Of Cooled Turbine

Higher turbine inlet temperature is one of effective means to improve gas turbine thermal efficiency, which makes harsh demands of the reliability of the high-pressure turbine. In order to reduce the thermal shock of turbine blades, if unchanged the original cooling structure, it is necessary to increase the amount of cooling air, which will reduce the overall efficiency. In the case of keeping the original cold air is changeless, by optimizing the cooling structure can improve the gas temperature at the same time improve cooling effectiveness, and then improve the overall efficiency.The traditional cooling structure design of the turbine is a simple combination of the finite design variables, which requires a lot of work force and the design cycle is long.With the development of optimization theory, the design of the complex cooling structure of the turbine is possible, which can reduce the consumption of human resources and shorten the design cycle.Based on the above engineering background, this paper has set up a platform cooling turbine optimization. This platform mainly includes air-cooled turbine parametric modeling, automatic mesh division, the CFD numerical calculation and the selection of the optimization strategy.The optimization platform is used to optimize the the layout of rows of film cooling holes of C3X. With the method of stepwise optimization, optimize the layout of the 5 rows film cooling holes of the front edge, and further optimize the layout of rows of film cooling holes of pressure side and suction side. Compared with the original model, the average cooling efficiency of the optimized leading edge region increased by 8.4%, the average temperature of the leading edge region decreased by 19.2 K. The average cooling effectiveness of the pressure surface increased of 1.1%,while the average cooling effectiveness of the suction surface increased of 5.5%. By applying the thermal insulation optimization results to the coupled calculation, the average temperature of the blade surface reduced by 3.2 K, and the heat transfer coefficient of the model is smaller than that of the original model.To further validate the engineering application of the optimization platform, it is applied to optimize the layout of multi rows film cooling holes of the modified marine gas turbine high pressure stator. In order to reduce the optimization time and improve the optimization efficiency, applied the three-order response surface model to fit the optimal design variables and objective function, and adopted the strategy of single objective optimization and multi-objective optimization. The results show that the multi-objective optimization of the cooling effectiveness increased of 11.4%,and average temperature of the blade surface reduced by 74.6 K. This platform can take full advantage of multi-objective optimization Pareto sets to express the optimization results, and then the designer can select different designs to meet different requirements.