对转涡轮内部流动机理及设计方法研究  

Counter-rotating turbine flow mechanism and aerodynamic design

作　　者：赵巍[1,2] 隋秀明 赵庆军[1,2] 徐建中[1,2] ZHAO Wei;SUI XiuMing;ZHAO QingJun;XU JianZhong(Institute of Engineering Thermophysics,Chinese Academy of Sciences,Beijing 100190,China;School of Aeronautics and Astronautics,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院工程热物理研究所,北京100190 [2]中国科学院大学航空宇航学院,北京100049

出　　处：《中国科学：技术科学》2020年第10期1376-1390,共15页Scientia Sinica(Technologica)

基　　金：国家科技重大专项(编号:2017-Ⅲ-0010-0036);国家自然科学基金(批准号:51776198)资助项目。

摘　　要：对转涡轮与常规涡轮相比具有效率高、重量轻和陀螺力矩小的优点,已广泛应用于先进航空发动机,正向着更高效率、级载荷和更优变工况性能方向发展.本文开展了1+1/2,1+1和1+3/2对转涡轮基元级分析,指出给定转速时,减小涡轮进口导叶出口预旋和增大高压涡轮动叶载荷是使低压涡轮动叶出口气流满足轴向约束的主要手段.根据进口总温1850 K、进口总压2.5 MPa和总膨胀比6等设计点要求,分析讨论了相同转速、进口内径和轮毂比的1+1/2,1+1和1+3/2对转涡轮通流设计和三维气动设计方法,实现涡轮高低压功比分别为2.0,1.8和1.5,效率分别为91.7%,91.8%和92.4%,高压动叶级载荷系数分别为3.2,2.7和2.4.其中1+1/2对转涡轮高压动叶中径出口相对马赫数达到1.60,采用缩扩流道叶型;1+1和1+3/2对转涡轮高压动叶出口相对马赫数分别为1.28和1.10,均采用渐缩流道叶型.分析了对转涡轮内部流动损失,指出对转涡轮相比传统涡轮具有更强的激波损失.提出了对转涡轮高压动叶吸力面无遮盖段内凹型线优化方法,降低了对转涡轮尾缘激波强度和尾迹宽度,1+1/2涡轮效率比采用常规设计方法提高0.3%,达到92.0%.给出了对转涡轮变工况特性,指出对转涡轮在高低压转子90%转速以上具有接近设计点的高效率,全工况性能无急剧衰退.针对1+1/2高低压转速分别为20%和10%工况,提出了低压动叶性能优化方法,提高低压涡轮效率15%、涡轮总效率5%,涡轮在发动机起动过程做功能力得到增强.Counter-rotating turbines have a high efficiency,low weight,and gyroscopic torque,which contribute to their wide use in advanced aerojet engines.Currently,counter-rotating turbines continue to be developed for higher efficiency,stage work loading,and better performance under design and off-design conditions.This paper presents velocity diagrams for counter-rotating turbines,showing that reducing the exit swirl of the turbine inlet nozzle and increasing the stage work loading of a high-pressure turbine rotor are main way to satisfy the turbine design constraints of an axial exhaust flow.According to the turbine design condition of an inlet total temperature of 1850 K,inlet total pressure of 2.5 MPa,and expansion ratio of 6,the through flow and 3D blade design for 1+1/2,1+1,and 1+3/2 counter-rotating turbines were conducted using the same rotating speeds,hub radius,and inlet hub-tip ratio.The output power ratios for the high-pressure and low-pressure stages were 2.0,1.8,and 1.5,respectively,with efficiencies of 91.7%,91.8%,and 92.4%,respectively,and working coefficients for the high-pressure rotors of 3.2,2.7,and 2.4 for the three types of turbines.The highpressure rotor of the 1+1/2 turbine has an exit relative Mach number of 1.6 at a 50%blade span and a convergent-divergent blade passage,whereas those of the 1+1 and 1+3/2 turbines were 1.28 and 1.10,respectively,and both had convergent blade passages.The flow losses of these turbines were investigated,showing that severe shock losses are present in counter-rotating turbines in contrast to traditional turbines.A shock loss restriction method using a concave suction side curve was consequently proposed to reduce the intensity of trailing edge shocks and the width of the wake.The efficiency of the 1+1/2 turbine is increased by 0.3%to 92.0%by using this method.The turbine performance characteristics are also presented and discussed.The turbine efficiency remained almost unchanged above a rotating speed of 90%,and there was no sharp drop in the off-design performance.

关 键 词：对转涡轮 气动设计 流动机理 变工况 

分 类 号：TK14[动力工程及工程热物理—热能工程]