发动机短舱溢流阻力的数值模拟

 为分析发动机溢流阻力的产生原因并为进气道-发动机匹配研究提供一定的技术支持,以典型的发动机短舱为研究对象,分析了短舱上的进气道阻力,并详细介绍了相应溢流阻力的数值计算方法。在对发动机短舱外流模拟时,通过引入两个和发动机参数相关的数值边界条件,即一个是定流量的发动机进气道入流边界,另一个是定总温总压的发动机喷流边界,避免了对发动机复杂内流的模拟。利用NACA-1-81-100发动机进气道作为标准算例,验证了数值方法的可行性。通过模拟发动机短舱在不同工作流量下的流动,认为发动机短舱的溢流阻力产生归因为溢流造成的发动机外表面的阻力变化,以及捕获流管变细导致的附加阻力增加。

Numerical Simulation About the Spillage Drag of Engine Nacelle

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.