整流罩有效负载填充效应变化规律及形成机理研究

摘要

For the problem of local SPL (Sound Pressure Level ) increasing caused by the payload filled in the launch vehicle fairing (fill effect problem),the equivalent models of the fairing and payloads are established using the sandwich plate theory. The interior acoustic characteristic of the fairing is simulated through FE-BEM (Finite Element-Boundary Element Method) and SEA (Statistical Energy Analysis) method,and then the influence of the payloads with different volume ratio and different shape on the fill effects is investigated.Besides,the mechanism and distribution characteristic of fill effect are studied from the point of view of mode frequency shift.The simulation and test results show that fill effect is associated with acoustic mode fre-quency shift caused by sound-vibration coupling.The shift ratio is greater at low frequencies than at high frequencies,which makes the fill effect more obvious.In that the payload fill factor can influence the shift ratio,fill effect will increase as the fill factor increases.Numerical computation based on FE-BEM and SEA provides an effective way to predict the payload fill effect.%针对有效负载填充导致的运载火箭整流罩内部局部声压级增大现象即填充效应问题,采用三明治夹芯板理论,建立了整流罩及负载的等效模型,利用FE-BEM和SEA法分别对运载火箭整流罩的低、高频段内声场特性进行了数值分析,研究了负载体积比和负载形状对填充效应的影响,从模态频率的角度对填充效应的形成机理及变化规律进行了解析.仿真与试验结果表明:填充效应与声振耦合作用引起的声学模态频率偏移有关,低频偏移幅度比高频更大,低频填充效应更加明显;填充负载体积比直接影响模态偏移的幅度,填充效应随负载体积比的增大而增大.基于FE-BEM及SEA的数值计算方法为有效负载填充效应的预测提供了分析手段.