Investigation On Optimization Design Method Of Gas Turbine Aerodynamic And Cooling

Gas turbine is widely used in the fields of aircraft propulsion and power generation, and plays a significant role in the civil economy and national defense. In the research and development of gas turbine, improving the throughflow design technique and increasing the inlet temperature/pressure are the main approaches to enhance the gas turbine performance. This demands us to explore advanced aerodynamic design method and turbine cooling design method.Numerical optimization method is applied to the turbine aerodynamic design and the cooling design in the last few years. By integrating optimization algorithm and CFD method, numerical optimization method can search the optimal design automatically, and the present design technique can slso be used at best by the optimization. At the same time, the component design period can be shortened and the design cost can be cut down effectively. So the numerical optimization method is drawn more and more attentions and many successful real turbine design cases with optimization technique are reported.In the turbine aerodynamic design, investigations on3D blade geometry optimization were carried out by a lot of scholars, and many achievements and optimization methods were reported. It is recognized that the turbine aerodynamic efficiency can be increased about one precentage by means of3D blade geometry optimization. However, the optimizations aimed at the meridional flow-path and the radial flow matching are fewly reported. Some investigations show that the improvement on meridional flow-path and radial flow matching has more potienal in the increase of turbine performance, and numerical optimization method can be very useful in those processes.In the turbine cooling design, it is infeasible to perform a real blade cooling geometry optimization, because the CFD computations time in blade cooling passage analysis are expensive. At the present time, a lot of investigations aimed at the simple cyclinder-like structure in the cooling passage optimization.The following investigations are performed in this paper:1. An aerodynamic optimization system for multi-stage axial-flow turbine was developed. The system consists of a quasi-one-dimensional method based on the meanline for the preliminary aerodynamic design of the whole turbine stages, a multi-elements method for the radial aerodynamic design of all blade rows, a novel multi-elements auto-blading method and an aerodynamic characterisitics computation method based on1.5dimensinal Euler equations.2. Intergrated the above design parts with Differential Evolution algorithm, a lot of aerodynamic optimization investigations were performaed, including the turbine meridinal flowpath optimization, the radial-matchaing design optimization, and the3D blade geometry optimization.3. Based on the multi-objective optimization software, IOSO NM, a turbine cooling optimization system is constructured. The system employed CAD software to generate parmaterized geometry and CFD software to assess the performace of cooling designs. In the optimization system, a ribbled straight cooling duct and a three-pass ribbed serpentine cooling passage are investigated by the nurmerical optimization technique.4. Using transient sigle-color liquid crystal capturing technique, a test rig for measuring heat transfer coefficient of cooling passage is set up. The three-pass ribbed serpentine cooling passage is used as a test sample to measure the heat transfer coefficient and the pressure drop.