Abstract: In order to provide a reference for the design of the Auxiliary Power Units (APU) air inlet system, the aerodynamic performance of a typical dual compressor configuration APU air inlet system with perforated protecting plates was studied using 3D CFD. The operating mode of the basic model with orifice ratio 0.479was investigated under the fixed proportion condition as well as the total mass flow condition. The results show that the outlet total pressure loss consists of several factors, such as throttle and mixing loss near the perforated plates, collision loss near the throat section,turning and boundary layer loss in the duct. The total pressure distribution is mainly affected by duct curvature in radial direction and by the imperforate area of the whole perforated plates in the circumferential direction. Meanwhile, the aerodynamic performances of the APU air inlet system with different orifice ratios were investigated as well. The results show that with the increase of orifice ratio, the total pressure recovery coefficient of the outlet increases accordingly. The APU air inlet system loss and the distortion of load section were mainly affected by perforated plates in small orifice ratio, but by duct curvature in large orifice ratio. The recommended orifice ratio is 0.4~0.6.

Key words: APU air inlet system; Perforated plates; Orifice ratio; Numerical simulation; Aerodynamic performance

摘要： 为给一类APU进气系统设计提供参考,利用CFD方法,对带多孔板的双压气机构型的APU进气系统气动性能进行三维数值模拟。对多孔板开孔率为0.479的基准模型按照定配比和定总流量工况进行了研究。结果表明:APU进气系统总压损失包括多孔板附近的节流、掺混损失,喉道段流股碰撞损失,流道转弯到出口段的转弯、附面层损失；总压分布在径向上主要受流道曲率影响,周向上主要受多孔板无孔区影响。同时研究了不同开孔率下该APU进气系统气动性能。研究发现:开孔率增大,总压恢复系数随之增加；小开孔率时系统总压损失和负载端畸变主要受多孔板影响,大开孔率时流道曲率影响成主要因素。建议开孔率在0.4~0.6选取。 

关键词: APU进气系统;多孔板;开孔率;数值模拟;气动性能 