多级轴流压气机甚高压部件设计探究

以大涵道比涡扇发动机总增压比由50∶1提升至70∶1为目标,设计了串接在某10级23∶1高压压气机之后的5级2.2∶1轴流压气机甚高压部件,探究以全轴流方式提高总增压比的方案的可行性。通过部件总体与一维设计,S2通流反问题与叶片造型,计算流体力学验证,在采用了各级正预旋、转子尖部大落后角、静子正弯等措施后实现了该设计。研究表明:在达到设计指标的情况下,该多级轴流甚高压部件的叶尖间隙可选择为0.2 mm,若取较为常规的0.3 mm叶尖间隙,则其大轮毂比、相对大叶尖间隙等几何特征,将导致失速裕度下降明显,稳定工作范围变窄。另外,在结构方面,全轴流甚高压部件方案还需要解决叶片数量巨大,级成本提高等问题。 

Design inquiry of an ultra-high-pressure-ratio component of multi-stage axial flow compressors

For increasing the overall pressure ratio from 50∶1 to 70∶1 of the high bypass ratio turbofan engine, a 5-stage ultra-high-pressure-ratio axial-flow component with pressure ratio of 2.2∶1 was designed, and connected to the exit of a 10-stage high-pressure compressor with pressure ratio of 23∶1. The feasibility to improve the overall pressure ratio with a complete axial-flow configuration was explored. The design was implemented through the process including component 1-D overall aerodynamic design, S2 through-flow inverse problem and blade modeling and 3-D computational fluid dynamics verification. The specific methods such as positive pre-whirl at each stage, large-deviation-angle rotor tip and positive bowed stator were used in the process. Under the condition of achieving the prescribed aerodynamic design parameters, it’s recommended to set the rotor tip clearances to 0.2 mm rather than 0.3 mm, otherwise the compressor stall margin would drop significantly and its stable working range would be narrowed due to the geometric characteristics of large hub-tip ratio and the relatively larger rotor tip clearances. In the terms of structure, the design may lead to some issues that must be solved before the compressors enter into service, such as a huge number of blades and the higher machining costs of each stage.