低雷诺数下轴流压气机转子3维流动特性数值模拟

Numerical Simulation on 3 Dimensional Flow Characteristics of Axial Compressor Rotorsat Low Reynolds Number

中文关键词:  轴流压气机  二次流  转子  低雷诺数  失稳  3维流动特性  航空发动机

英文关键词:axial compressor  secondary flow  rotor  low Reynolds number  instability  three-dimensional flow characteristics  aeroengine

中文摘要:

      为了探究轴流压气机转子在低雷诺数下的性能及3维流动特性，对跨声速转子压气机Rotor37在地面和高空下的气动 性能和内部流场进行了数值模拟。结果表明：在20 km高空下，压气机在近失速点的总压比和绝热效率分别降低了8.0%和5.3%， 喘振裕度降低了3.1%；在低雷诺数下，转子吸力面上的流动分离位置会提前掺混且更剧烈，导致分离附面层增加，同时由于吸力 面附面层较厚，激波与边界层的作用加强，减小叶表附面层内低能流体向上运动的压力分量，低能流体在离心力的作用下更容易 向叶顶附近迁移，这可能是触发转子工作失稳的重要因素；在低雷诺数下，叶片根部吸力面在84%轴向弦长处发生完全分离并形 成角涡，在其向叶顶移动的过程中形成脱落涡，角涡和脱落涡面积明显增加，这是引起转子低雷诺数工作效率降低的重要原因 之一。

英文摘要:

      In order to explore the performance and three-dimensional flow characteristics of axial compressor rotors at low Reynolds number， the aerodynamic performance and internal flow field of transonic rotor compressor Rotor37 at ground and high altitude were numerically simulated. The results show that at an altitude of 20 km ， the total pressure ratio and adiabatic efficiency of the compressor near the stall point are reduced by 8.0% and 5.3%， respectively， and the surge margin is reduced by 3.1%. At low Reynolds numbers， at the flow separation position on the suction surface of the rotor， the flow mixing will be in advance and more intense， resulting in an increase in the separation boundary layer. At the same time， due to the thicker surface boundary layer， the interaction between the shock wave and the boundary layer is strengthened， which reduces the pressure component of the upward movement of the low-energy fluid in the boundary layer of the blade surface. The low-energy fluid is more likely to migrate to the vicinity of the blade tip under the action of centrifugal force， which may be an important factor triggering the instability of the rotor. At low Reynolds numbers， the suction surface of the blade root completely separates at 84% of the axial chord length and forms a corner vortex， and a shedding vortex is formed during its movement to the tip of the blade. The area of the corner vortex and the shedding vortex increases significantly， which is one of the important reasons for the decrease in the working efficiency of the rotor at low Reynolds numbers.