超燃冲压发动机推力性能评估方法

Assessment of Scramjet Engine Thrust

关键词:  超燃冲压发动机  机体推进一体化  脉冲燃烧风洞  推力  阻力  比冲

Key words:  Scramjet engine  Aero-propulsion integration  Pulsed combustion heated wind tunnel  Thrust  Drag  Specific impulse

摘要:

超燃冲压发动机与飞行器紧密耦合，使得在地面试验直接测量发动机流道有效推力非常困难。为了更有效获得发动机推力性能，提出了一种基于机体推进一体化性能试验的评估方法，基于脉冲燃烧风洞带动力一体化测力试验直接获得飞行器的整机净推力。基于净推力加机体外阻的方法获得了发动机有效推力。同时提出了一种通过流量计测量飞行器机体外阻的试验技术，并对测量误差进行了分析(均方根误差小于 2.54%)。与传统的台架推力差减内阻的方法相比，该方法把发动机流道内阻计算转为飞行器机体外阻计算或测量，为超燃冲压发动机推力性能评估提供了一种全新思路。

Abstract:

Scramjet closely coupled with the aircraft，making it very difficult to directly measure the effec.tive thrust of the engine in the ground test. In order to obtain the engine thrust performance more effectively，an evaluation method based on the aero-propulsion integrated test is proposed. The net thrust of the aircraft with en.gine integrated is obtained directly from the force measuring test of pulsed combustion heated wind tunnel. Thenthe effective thrust of the engine is obtained based on the net thrust plus the external drag of the body. At the sametime，a test technique for measuring the external drag of the aircraft body by a flowmeter is proposed. The mea.surement error is also analyzed(the root mean square error is less than 2.54%). Compared with traditional meth.od which applied the difference of measured total axis forces between fueled and unfueled engine status minus thecomputed flowpath drag to get the engine thrust，this method transforms the calculation of the internal drag of theengine flow path into the calculation or measuring external drag of the aircraft and provides a new idea for thethrust performance evaluation of the scramjet engine.