固体火箭发动机燃气射流流场和声场数值计算

摘要

燃气射流噪声是固体火箭发动机工作过程中的主要噪声源之一，射流流场的参数对其产生的射流噪声有重要影响。通过大涡模拟( LES)对不同尺寸喷管形成的超声速高温射流进行了三维非稳态数值模拟，随后在合适的声源面中，采用FW-H( Ffowcs Williams-Hawkings)声学模型和傅里叶变换得到了燃气射流噪声声压级的空间分布。计算结果表明，随着喷管尺寸增大，超声速射流核心区变大，喷口流场波节数增加，对喷管尾流场的影响域扩大，其产生的射流噪声也增强；燃气射流噪声辐射有较强的指向性，在射流轴向30°角方向噪声声压级最大，与相关文献中的试验结果比较吻合。研究结果可为后续固体火箭发动机降噪设计提供参考。%Noise of gas jet is one of the main noise sources for solid rocket motor,and the jet flow field parameters play an im-portant role in the radiated noise generated. Large Eddy Simulation ( LES) was applied to simulation of the 3D unsteady supersonic hot jet flow generated by nozzles with different size.The jet noise distribution of overall sound pressure level was obtained based on the Ffowcs Williams-Hawkings (FW-H) acoustics equation and Fourier transform.The calculation results show that the jet core,the wave number,the flow-field and the sound pressure level of the jet noise sound field increase with the increase of nozzle sizes.The jet noise is strongly directional,and it reaches maximum at the angle of 30°away from the axis of jet center.The results can be taken into consideration for reduction of solid rocket engine jet noise.