Computational Investigation of a Boundary-Layer Ingesting Propulsion System for the Common Research Model

The present paper examines potential propulsive and aerodynamic benefits of integrating a Boundary-Layer Ingestion (BLI) propulsion system into the Common Research Model (CRM) geometry and the NASA Tetrahedral Unstructured Software System (TetrUSS). The Numerical Propulsion System Simulation (NPSS) environment is used to generate engine conditions for Computational Fluid Dynamics (CFD) analyses. Improvements to the BLI geometry are made using the Constrained Direct Iterative Surface Curvature (CDISC) design method. Potential benefits of the BLI system relating to cruise propulsive power are quantified using a power balance method, and a comparison to the baseline case is made. Iterations of the BLI geometric design are shown, and improvements between subsequent BLI designs are presented. Simulations are conducted for a cruise flight condition of Mach 0.85 at an altitude of 38,500 feet, with Reynolds number of 40 million based on mean aerodynamic chord and an angle of attack of 2° for all geometries. Results indicate an 8% reduction in engine power requirements at cruise for the BLI configuration compared to the baseline geometry. Small geometric alterations of the aft portion of the fuselage using CDISC has been shown to marginally increase the benefit from boundary-layer ingestion further, resulting in an 8.7% reduction in power requirements for cruise, as well as a drag reduction of approximately twelve counts over the baseline geometry.