Effect of airframe/inlet integration on inlet performance

The aerodynamic interference between an integrated airframe/inlet configuration of a supersonic civil aircraft directly affects inlet performance. This study established geometric models for both isolated inlets and integrated airframe/inlet configurations while designing and constructing an experimental setup for integrated airframe/inlet systems. After experimentally validating the accuracy of the numerical solution methods, this study systematically investigated the effects of angle of attack on internal flow characteristics within isolated inlets. Through a comprehensive analysis, the airframe's influence on both the internal and external flow properties of inlets was examined, ultimately revealing the aerodynamic mechanism through which the airframe affects inlet performance. The results indicate that under angle-of-attack conditions, the total pressure recovery coefficient decreases, while the distortion index increases in isolated inlets. The airframe significantly influences inlet total pressure recovery and distortion indices; specifically, at α = 0° and α = 2°, isolated inlets exhibit 3.05% and 3.25% higher total pressure recovery coefficients than integrated configurations, respectively. At α = 0°, isolated inlets show a 2.44% lower distortion index than integrated configurations, but at α = 2°, this relationship reverses with isolated inlets demonstrating 3.23% higher distortion indices. Regarding external flow characteristics, expansion waves generated by the airframe surface elevate the inlet entrance Mach number beyond freestream values, increasing total pressure losses.