论文部分内容阅读
用发动机等效出口直径做为特征尺寸,并假设出口参数相同(实际上,对同一类型火箭发动机,出口参数很相似)。用出口直径对观测点位置进行规一化,用出口直径和推力对声压级规一化,考虑到在声传播过程中,大气衰减与频率的二次方成比例,高频声波比低频声波衰减快,在喷口附近频谱的谱峰频率较高,在远离喷口处,谱峰频率移向低频,实测结果也是如此,因此引出了一个规一化谱形修正因子,连同出口直径一起对频率进行规一化。最后由‘数据’火箭的实测数据得到了三条曲线。对误差做了分析,并对部分误差提出了修正方法。可给出新火箭任一位置的总声压级和三分之一倍频程频谱。
The equivalent outlet diameter of the engine is taken as feature size and the exit parameters are assumed to be the same (in fact, the exit parameters are very similar for the same type of rocket motor). The outlet diameter of the observation point to normalize the diameter and thrust with the outlet pressure on the standardization of regulation, taking into account the sound propagation in the process, the attenuation of the atmosphere is proportional to the square of the frequency, high frequency sound waves than low frequency sound waves The attenuation is fast and the peak frequency of the spectrum near the nozzle is higher. The frequency of the peak shifts to low frequency away from the nozzle. The same is true with the measured results, thus leading to a normalized spectral correction factor along with the exit diameter for frequency Regularized. Finally, there are three curves obtained from the measured data of the ’data’ rocket. The error was analyzed, and some of the error correction method proposed. Give the total sound pressure level and one-third octave spectrum at either location of the new rocket.