二次喷射阀门作动对侧向力的影响

针对潜入式喷管燃气二次喷射推力矢量控制系统,利用AUSM+格式,并结合Realizable k-ε湍流模型,对喷管内二次喷射流场进行数值模拟。主要研究二次喷射阀门作动过程中侧向力的变化规律,分析正弦波、三角波2种作动方式和5、7、10 Hz 3种频率对侧向力的影响规律。结果表明,在阀动过程中侧向力变化与阀门开度变化趋势相同,大体上侧向力随阀门开度增加而增加,随阀门开度减小而减小,但存在一定的时间和空间滞后,侧向力变化滞后于阀门位置变化,最大侧向力出现在半个周期以后,即最大开度出现时刻之后,且阀门重新闭合后,很短时间内仍有侧向力残存,相同开度下,侧向力有如下大小关系:关闭过程大于准稳态,二者又大于开启过程中的侧向力;从最大侧向力出现时刻分析滞后时间τD,在波形上三角波下滞后时间τD要大于正弦波下的τD,在频率上10 Hz下的τD最大,5 Hz下的τD最小;从侧向力相对残存时间τR分析时间滞后,在波形上三角波下的τR要大于正弦波下τR,在频率上7 Hz下的τR最大,5 Hz下的τR最小。

Effect of valve actuation mode and frequency on lateral force in gas secondary injection system

Combining AUSM+format with Realizable κ-ε turbulence model,change law of lateral force in valve actuation process was explored and the effect of valve actuation mode (triangular wave,sinusoidal wave) and frequency (5,7 and 10 Hz) on lateral force was analyzed based on the simulation of flow field of nozzle in gas secondary injection system.Results show that change law of lateral force is similar with that of valve opening,in general,lateral force increases with the increasing of valve opening,and there is delay on time and space compared with valve actuation.Variations of lateral force lag behind that of the valve position.The largest lateral force occur after half period,while valve opening is less than the maximum value.There are still remnants of lateral forces in a short time after the valve is closed again.In the same valve opening,the lateral force in the closing process is greater than that of quasi-steady state,lateral force in opening process is the least among of them.Delay time τD of triangular wave is greater than that of sinusoidal wave in the three frequencies.τD of 10 Hz is the greatest and τD of 5 Hz is the least among them in the two valve actuation mode based on the delay time of largest lateral force.Restoration time τR of triangular wave is greater than that of sinusoidal wave in the three frequencies.τR of 7 Hz is the greatest and τR of 5 Hz is the least among them in the two valve actuation mode based on the restoration time of largest lateral force after the valve is closed again.