Quantification of the boundary layer ingestion benet for the D8-series aircraft using a pressure rake system

Abstract

This thesis presents the results of experiments carried out at NASA Langley Research Center (LaRC) 14'x22' Subsonic Wind Tunnel to determine the aerodynamic boundary layer ingestion (BLI) benet for the D8 aircraft advanced transport concept. The experiments involved a back-to-back comparison between two D8 aircraft configurations: a podded propulsion system (non-BLI) and a fuselage integrated propulsion system (BLI). The BLI benet was evaluated from ow surveys upstream and downstream of the propulsor using a rotating rake system for the two configurations. The BLI benefit, defined as the mechanical flow power saving at cruise conditions (zero net streamwise force), from the BLI configuration relative to the non-BLI configuration, was found to be 8.2% +/- 0:8%. The experimental-computational approach and the sensitivity analysis of the estimated BLI benefit to uncertainties such as flow angles and instrumentation errors are described in the thesis. The benefits and drawbacks of the rotating rake measurement technique used in the D8-series powered model aircraft experiments are also discussed.