The study of jet noise characteristics of liquid rocket engines is a prerequisite for evaluating the noise level of rockets and effectively controlling the noise. To obtain the effect of engine operating and structural parameters on jet noise, the Large Eddy Simulation combined with the FW-H integration method is applied for the scaled engine with guide groove under different chamber pressures and nozzle expansion ratios. The simulation results show that the noise field distribution of the jet with a guide groove is highly symmetrical and has obvious directivity. The noise caused by jet impingement on the guide groove is strongly correlated to the distribution of high vorticity regions. Remarkably, higher chamber pressure leads to longer potential jet length, higher noise sound pressure levels, and greater enhancement effect of impact on noise. However, the frequency spectral characteristics are basically invariant. When the chamber pressure is constant, the increment of the nozzle expansion ratio in a certain range results in lower noise peak frequency and weaker impact effect.

中文翻译：

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带导槽液体火箭发动机喷流噪声特性大涡模拟

液体火箭发动机喷气噪声特性的研究是评价火箭噪声水平、有效控制噪声的前提。为了获得发动机工作和结构参数对喷气噪声的影响，将大涡模拟结合FW-H积分方法应用于具有导槽的缩尺发动机在不同室压和喷嘴膨胀比下的情况。仿真结果表明，带导槽的射流噪声场分布高度对称，且具有明显的方向性。射流冲击导槽产生的噪声与高涡度区域的分布密切相关。值得注意的是，腔室压力越高，潜在射流长度越长，噪声声压级越高，对噪声的影响增强效果越大。然而，频谱特性基本不变。当腔室压力一定时，喷嘴膨胀比在一定范围内增大，噪声峰值频率较低，冲击效果较弱。