渐变截面热声波导管内的声流影响因素分析

Investigation on influencing factors of acoustic streaming in thermoacoustic waveguides with slowly varying cross-section

通过理论分析和数值仿真,对渐变截面热声波导管内声流各影响因素进行了具体的分析,并给出了不同情形下波导管内的声流速度分布特性曲线。研究表明,热物理参数对渐变截面导致的声流变化无影响,针对具体的声场设计合适的截面变化形式可以使得管内声流在整体上得到一定程度的抑制或加强。此外,当波导管截面尺度与热穿透深度同数量级时,轴向时均温度分布对声流的影响十分显著。当不存在非零时均温度梯度时,热传导效应对声流的影响在管截面尺度为黏性穿透深度约10至20倍量级时最大。

The influencing factors of acoustic streaming in thermoacoustic waveguides with slowly varying cross-section are analyzed based on theoretical analysis and numerical simulation. The distribution curves of acoustic streaming velocity in waveguides with different characteristic scales are presented in several specific cases. The results show that appropriate forms of varying cross-section can strengthen or weaken acoustic streaming for specific acoustic fields and the thermophysical parameters have no effect on this part. In addition, the influence of time-average temperature distribution on acoustic streaming is substantial in tubes with a width of the order of the thermal penetration depth. Without time-average temperature distribution, the effect of heat conduction on acoustic streaming is great in tubes whose width is an order of about 10 to 20 times the viscous penetration depth.