不同喷嘴射流流场结构及噪声

Flow field structure and noise for different nozzles

关键词:  喷嘴形状  大涡模拟  计算气动声学

Key words:  Nozzles shape  LES  Calculation of aeroacoustic

摘要:

针对射流产生噪声的问题,应用Smagorinsky涡粘性模型和二阶精度的有限体积法对不同喷嘴的外部流场进行了大涡模拟,研究了不同喷嘴外部流场非定常结构特性。射流噪声计算采用FW-H(Efowcs Williams & Hawkings)方法,给出了三种喷嘴的声压级。并以Ma=0.9时直喷嘴计算和实验结果为例,分析了在有限频率段内声压级的变化规律,并与实验结果进行了比较。结果表明:在同等条件下,收缩喷管的噪声等级最大,环型喷管的噪声等级最小。

Abstract:

To address jet noise problem, second order upwind scheme Roe and Smagorinsky subgrid model were applied for different nozzles flow field numerical simulation. FW-H equation was used to calculate jet aeroacoustic field and acoustic level. The characteristic of acoustic level was analyzed for the nozzle with constant section at Ma=0.9. The results indicate that under the same condition the acoustic level of contraction nozzle is the largest and the circular nozzle is the least.