运载火箭整流罩内声场空间相关特性研究

Research on spatial correlation characteristics of interior acoustic field of launch vehicle fairing

运载火箭起飞段发动机喷流经过导流槽、发射台产生的噪声载荷会对地面发射设备造成一定的破坏,由噪声引发的振动对于运载火箭自身也会造成严重影响。总声压级、声功率谱密度及空间相关系数3个参数可描述完整的噪声场,但空间相关系数关注很少。由于空间相关特性的差异,同一声压级不同性质的噪声场在结构上产生的振动响应不同。从噪声场空间相关的基础理论出发,给出了空间相关理论曲线,研究了混响室空间相关特性;以某型号运载火箭整流罩为研究对象,开展星箭系统级噪声试验,获取了运载火箭表面声场分布规律,并基于试验数据研究了空间相关归一化表征方法,对比分析了混响室和整流罩内声场特性,结果表明整流罩内声场与混响声场空间相关特性接近,为运载火箭载荷与环境设计提供输入,为整流罩及有效载荷噪声环境试验方案设计提供支持。

During lift-off phase of launch vehicle flight, the noise produced by the deflector tunnel and launch deck when the engine’s plume flow away may destroy the ground launching device. And the noise environment can excite the vibration of launch vehicle. The characteristics of the acoustic field highly depend on total sound pressure level, noise power spectrum density and spatial correlation coefficient. Among them the spatial correlation coefficient is less investigated. However, the acoustic fields with different spatial correlation coefficient, but the same sound pressure level can induce different structural vibration response. In this paper, based on the theory of spatial correlation characteristic of acoustic field, the theoretical curves of spatial correlation are obtained and the spatial correlation characteristic of reverberation chamber is studied. Acoustic test of satellite-rocket system level is developed applying a type of launch vehicle fairing and the regular distribution of acoustic field for launch vehicle is obtained. Based on the test data, the normalized characterization method of spatial correlation is validated. Compared with the interior acoustic field between reverberation chamber and fairing, the spatial correlation characteristic of reverberation chamber is close to the fairing. All these studies can provide the input for load and environment design and provide support for the fairing and satellite ground noise environmental test program.