外流对塞式喷管流场和性能的影响

Effects of free stream on flowfield and performance of linear aerospike nozzle

在四个不同高度上选择有代表性的外流马赫数,计算和对比了不同外流下塞式喷管性能的降低和塞锥表面的压强分布,数值模拟研究了外流对塞式喷管流场和性能的影响.结果表明,外流造成的性能损失主要体现在运载器底部阻力增加和塞锥表面压强降低两方面.在中低空以下,运载器底部推力和塞锥推力均随外流马赫数的增加而减小,飞行中外流对性能的影响随高度的增加而减弱,从低于设计点的某一高度开始塞锥推力不再受外流影响.低马赫数亚声速外流时,性能损失随外流马赫数的增加成近似线性增加;跨声速外流时,性能损失突然出现较大幅度增加;在继续的超声速范围内,性能损失随外流马赫数增加只有小幅增长.

Numerical studies on effects of free stream on flowfield and performance of aerospike nozzle were presented. Aerospike nozzle performance losses and pressure distribution along plug surface were computed and compared at four different altitudes with typical free stream Mach numbers. It is shown that aerospike nozzle performance losses caused by free stream primarily result from increase of lift body base drag and decrease of plug pressure distilbution. At mid and low altitudes, thrust of lift body base and plug ramp decreases with increasing free stream Mach number. The effects of free stream on performance decrease with increasing altitude, and from a certain altitude lower than design point thrust of plug ramp is not influenced by the free stream any more. For subsonic free stream, performance losses almost linearly increase with increasing Mach number. For transonic free stream, sudden performance degradation occurs. For the further supersonic range, performance losses increase slightly with increasing Mach number.