Investigation Of Aerodynamic Design Method And Unsteady Flow Characteristics Of Ultra-highly Loaded Turbine

Through various stage of scheme implementation development in United States, such as in-service aeroengine, demonstrator, advanced program-IHPTET etc., the trends of U.S. aeroengine turbine development may be summarized as:conventional→highly loaded→1+1 counter-rotating→1+1/2 counter rotating. High work capacity turbine is the key component for both highly loaded turbine and counter rotating turbine. By using highly loaded turbine, the stage work capacity will be increased and the stages of multistage turbine will be reduced, thus the engine thrust to weight ratio may be increased. Comprehensive research work show that highly loaded turbine have become an important direction of aeroengine turbine.Based on the previous numerical and experimental research, ultra-highly loaded turbine design methods and numerical simulation were studied in this paper, experimental results were adopted to verify the design methods and numerical results, and the ultra-highly loaded turbine design system is established. The main content in this paper is listed as follows:1. The transonic turbine blade airfoil is designed by parametric design method. The control parameter selection method is investigated in this paper. Exit-to-throat width ratio, throat location and trailing edge thickness are key control parameters for convergent-divergent turbine cascade, which determine the performance of the turbine cascade. After theoretical analysis, the selection method of exit-to-throat width ratio, throat location and trailing edge thickness, were presented, then the numerical simulation was adopted to verify the validity of the method.2. The method on how to choose blade-to-blade passage exit-to-throat width ratio of 3D transonic blade was presented. In addition, the corresponding regulation along the blade height was also proposed. Based on this, the high pressure rotor of vaneless counter-rotating turbine(VCRT) was redesigned with the adequate blade-to-blade passage exit-to-throat width ratio. Numerical simulation results showed that the performance of the redesigned high pressure rotor has been improved significantly, which was also verified by experimental results. 3. Ultra-highly loaded turbine design method was investigated. The purpose is to find the difference between traditional turbine design method and the ultra-highly loaded turbine design method, and to build the ultra-highly loaded turbine aerodynamic design system. Based on the traditional aerodynamic design system, modification on one dimensional model and quasi three dimensional model were investigated. then final aerodynamic design system was set up, which was clarified by systemtical numerical system.4. Unsteady flow characteristics in the ultra-highly loaded turbine were investigated, including unsteady wake, interaction between rotor and stator, and the unsteady effect to improve the performance of the turbine.