关键词: 航空发动机, 计算流体力学, 进气道阻力, 溢流阻力, 附加阻力, 入口流量系数

Abstract:

The purpose of this paper is to analyze the causes for the spillage drag and provide some technical methods for inlet-engine matching. The aerodynamic inlet drag forces are analyzed and a numerical method for computing the spillage drag is introduced in detail by using a typical engine nacelle as the research object. Two numerical boundary conditions related to the engine's parameters are introduced in the nacelle flow simulation around the engine, so as to avoid the complex internal flow simulation in the engine. One is for the nacelle inlet where the mass flow is known; the other is for the engine exhaust where the stagnation temperature and pressure are known. The validity of this numerical method is proved by utilizing the NACA-1-81-100 nacelle inlet in a standard numerical test. Finally, by simulating and analyzing the flows around the engine nacelle in different inlet mass flow ratios, it is concluded that the spillage drag is attributed to the variation of the cowl drag owing to the spillage flow and the increase of additive drag due to the tapering capture stream tube.

Key words: aircraft engines, computational fluid dynamics, inlet drag, spillage drag, additive drag, inlet mass flow ratio