Extension of the Throughflow Solver for Predicting the Aerodynamic Performance of Fans With Inlet Distortion

Abstract Next-generation aircraft with boundary layer ingesting (BLI) engines can reduce fuel consumption but pose challenges for fan and compressor operation due to inlet distortion. To optimize the design of such engines, it is essential to assess the impact of nonuniform inlet flow on stability and performance, with the final result of a distortion-tolerant machine. One of the first steps in this process is estimating the aerodynamic performance using fast but reliable mathematical models. This article presents an extension of the existing throughflow solver that predicts the effects of the upstream distortion. The proposed method, based on the parallel compressor theory, introduces multiple planes to accurately define and track the circumferential distribution of parameters as they advance through the machine. It applies to all types of distortion: total pressure, total temperature, and swirl. The model is demonstrated for a high-pressure, low hub-to-tip diameter ratio fan with nonuniform total pressure at the inlet. Flow physics associated with distortion is analyzed using results from full-annulus unsteady Reynolds-averaged Navier–Stokes (RANS) simulations for three operating points: near stall, design, and near choke. The flow field results are compared with the computational fluid dynamics (CFD) data at the design point. The overall performance is evaluated against a clean inlet case.