多喷管超声速射流噪声的实验及数值模拟研究

Experimental and numerical simulation on supersonic multi-jet noise

为分析多喷管超声速燃气射流的噪声特性,对四喷管射流进行了实验和数值模拟研究.数值仿真采用大涡模拟结合Ffowcs Williams&Hawkings声学模型计算四喷管射流噪声,并与实验测量的噪声结果相对比以验证数值计算方法的可靠性.结果表明,仿真结果与实验结果变化趋势一致,其中远离地面的测点的总声压级与实验值相对误差为1.2%左右,验证了所采用的数值方法可准确预测多喷管超声速射流噪声;在高度欠膨胀状态下,四喷管的四束射流间存在相互干扰,并在四束射流合并后流动迅速转变为湍流状态;射流下游的大尺度湍流混合噪声是四喷管射流噪声的主要来源,总声压级沿射流方向最大.研究结果可为超声速喷管及其降噪方案设计提供参考.

In order to analyze the noise characteristics of supersonic multi-jet gas,this paper carries out experimental and numerical simulation of the quadruple-jet.In the numerical simulation,large eddy simulation combined with Ffowcs Williams&Hawkings acoustic model is used to calculate the quadruplejet,and the noise results are compared with those of the experimental measurement to verify the reliability of the numerical calculation method.The results show that the variation trend of the simulation results fits well with the experimental results,in which the relative error of the total sound pressure level of the measuring point far from the ground between the simulation and the experiment is about 1.2%.It is therefore verified that the numerical method used can accurately predict the supersonic multi-jet noise.In the highly under-expanded state,the four jets from the quadruple-jet nozzles interact with each other,and the flow rapidly changes into turbulent state after the merging of the four jets.The large scale downstream mixed noise turbulent of the jet is the main source of the quadruple-jet nozzles,and the total sound pressure level is the highest along the jet direction.The research results provide a reference for the design of supersonic nozzles and their noise reduction scheme.