Study on Design Compliance of Civil Turbofan Engine with the Requirements Defined in FAR 33.65

Engine surge and stall characteristics is an important safety issue that must be certificated before the engine type certificate (TC) approval. In this paper, design requirements of airworthiness regulation FAR 33.65 "Surge and stall characteristics" are established for five critical engine operation conditions, namely throttle transients, Bodie transients, starter assisted starts, windmill starts, and quick windmill relights. The design requirements consider all influencing elements analysis such as throttle level angle (TLA) movement, ambient temperature, inlet distortion, customer bleeding, power extraction, manufacturing/rigging/controlling tolerances as well as the critical engine condition analysis and pass/fail criteria for measuring design. Furthermore, one of the design requirements, inlet distortion, is selected to illustrate the simulation technique. This analysis technique uses the intake model as simulation object and aircraft crosswind as input conditions. Finally, the distortion intensity at the intake aerodynamic interface plane (AIP) is calculated by using CFD, which is one of the design inputs for engine stability analyses. (C) 2014 Published by Elsevier Ltd.