Design Optimization of Complex Total Pressure Distortion Screens for Gas Turbine Engine Testing

Abstract

Abstract. In a gas turbine engine, inlet flow distortion occurs due to factors such as flow separation in the aircraft inlet due to aircraft maneuvers and flight conditions. The distorted inlet flow significantly impacts the compressor performance, reducing the efficiency and operability of the gas turbine engine, as it can provoke early stall or rotating stall and cause aeromechanical issues. In a compressor ground test facility, distortion screens are employed to simulate the distorted inlet flow experienced in flight conditions. In the present work, a methodology is developed to design complex total pressure distortion screens. First, the total pressure loss characteristics of uniform porosity screens are evaluated by computations for screen porosities ranging from 0.20 to 0.90 and inlet Mach numbers ranging from 0.01 to 0.67. The influence of porosity on the total pressure loss for various inlet Mach numbers is highlighted in both incompressible and compressible flow regimes. Second, an inverse design methodology is formulated with the objective function to minimize the difference between the target and achieved total pressure patterns. Finally, this inverse design methodology is posed as an optimization problem, which is then iteratively solved using a gradient-based method until the target total pressure pattern is obtained. The proposed design optimization methodology is tested for several cases including actual gas turbine distortion patterns. The present work resulted in a robust design framework that can be utilized to design distortion screens based on the target total pressure distortion pattern for arbitrary inlet Mach numbers.