典型特征参数对大转折APU进气道飞行性能影响的数值研究

Numerical Study on Effects of Typical Characteristic Parameters on Flight Performance for Rapid Turning APU Inlet

关键词:  APU进气系统  典型特征参数  气动性能  分离损失  数值仿真

Key words:  APU intake system  Typical characteristic parameters  Aerodynamic performance  Separation loss  Numerical simulation

摘要:

为了给一种迎风开门式的辅助动力系统（APU）进气系统设计提供参考，采用基于后缘线轮廓及面积变化规律的参数化设计方法，通过对唇边顺滑修型，可以与唇口的锯齿前缘配合形成斜向下的进口段，利用数值模拟研究了进口形状、前缘面曲率和喉道位置这三个特征参数对此类大转折APU进气道性能的影响。计算结果表明：APU进气道损失主要来自于分离损失，进口形状主要影响导流面转折程度和进气道内压力梯度变化，前缘面曲率影响了分离区的尺度和强度，其中，前缘面曲率对出口气动性能影响较大，在设计状态下，适当增大前缘面曲率可使得出口总压恢复系数增大0.81%。在后缘面曲率不变的情况下，通过合理安排进口形状、前缘面曲率和喉道位置，可有效推迟分离的发生，减弱分离区强度。另外，在正攻角和侧滑状态下也表现出相同的趋势。

Abstract:

In order to provide a reference for the design of an auxiliary power system （APU） intake system with an APU flap， a design method based on the trailing edge line profile and area change rule is adopted. It can be matched with the serrated leading edge of the lip to form an oblique downward inlet section by smoothing and reshaping the lip. Numerical simulation is introduced to study the influence of the three characteristic parameters of inlet shape， leading edge surface curvature and throat position of sharp turning APU inlet performance. The results show that the APU inlet loss mainly comes from the separation loss， the inlet shape mainly affects the turning degree of the guide surface and the pressure gradient change， the leading edge curvature affects the size and strength of the separation zone. Among them， the curvature of the leading edge has a great influence on the aerodynamic performance of the outlet. In the design state， increasing the leading edge curvature can increase the total pressure recovery coefficient by 0.81%.When the trailing edge surface remains unchanged， the occurrence of separation can be effectively delayed， the strength of the separation zone is weakened， and the aerodynamic performance at outlet can be improved by reasonably arranging the inlet shape， the leading edge surface curvature and the throat position. In addition， the same trend is also shown in the forward angle of attack and sideslip.