近地点变轨发动机高空喷管性能预示研究

Altitude performance prediction of perigee kick motor nozzle

关键词:  火箭发动机喷管  高空仿真  二相流  分离流  数值仿真  性能预测

Key words:  Rocket engine nozzle  Altitude simulation  Two phase flow  Separated flow  Numerical simulation  Performance prediction

摘要:

对长征 2E火箭近地点变轨发动机EPKM高空喷管的地面性能和高空性能进行了预示。在喷管跨声速区,气相采用显式MacCormack差分格式、颗粒相采用特征线法,而在喷管超声速区采用特征线法,数值求解轴对称二维无粘两相流动模型。结合喷管内的气流分离准则预测发动机地面工作时的性能,同时根据地面试验数据外推发动机的高空性能,与实测性能数据比较,平均推力相对误差约为5 6%和1 5%左右;而直接对发动机高空工作时的满流状态喷管进行数值模拟所得的发动机平均推力与实测性能数据比较相对误差约为1 7%左右。研究表明,所采用的流动模型、气流分离准则和数值方法对高空喷管不同工况下的性能进行工程预示是有效的。

Abstract:

Ground and altitude performances of the LM 2E perigee kick motor (EPKM) altitude nozzle were predicted. The explicit MacCormack difference scheme for gas phase and the characteristic method for particle phase were employed in the nozzle transonic flow region, and in the supersonic flow section the characteristic algorithm was employed, to numerically solve the two dimensional axis symmetrical non viscous two phase flow model. Based on the gas flow separation criterion, the nozzle ground performance was predicted,meanwhile, the nozzle altitude performance was also calculated extrapolatively by using the ground test data. The predicative average thrusts have relative errors of approximate 56% and 15%, respectively, when compared with the measured values. The average thrust from simulating directly the altitude nozzle with full flow status gives a relative error of 17% approximately when compared with the measured value. The current studies show that the employed two phase flow model, gas flow separation criterion and numerical method are effective to predict the performance of the altitude nozzle at different operating statuses in practice.