Abstract

This study analyzed the acoustic energy transfer process in expanded pipe of heat exchangers based on the field synergy principle. The synergy between the flow field and the acoustic field was deduced theoretically based on the energy and momentum equations pertaining to the acoustic field. The synergy angle of the flow field and the acoustic field was calculated numerically. The noise propagation process in the expanded pipe was measured experimentally. The results show that the sound pressure level and synergy angle both increase with the increase in flow velocity, whereas the acoustic energy transfer process decreased with the increase in synergy angle. An extended outlet of the expanded pipe segment can reduce the flow noise magnitude with a lower pressure drop. The flow noise can reach 123 dB and the pressure drop is 37.3％ and 24.7％ less than other cases. In conclusion, the theoretical analysis, experimental tests, and numerical simulation method are developed to study the acoustic energy transfer process in segments of expanded pipe based on synergy principle of flow and acoustic fields.

摘要

本研究基于场协同原理分析了换热器膨胀管内的声能传递过程。基于声场的能量和动量方程，从理论上推导出了流场和声场的协同作用。数值计算了流场和声场的协同角。对膨胀管内的噪声传播过程进行了实验测量。结果表明，声压级和协同角均随着流速的增加而增加，而声能传递过程随着协同角的增加而减小。膨胀管段的扩展出口可以降低流动噪声幅度，同时压降更低。流动噪声可达123分贝，压降为37.3％和24。比其他情况少7％。综上所述，基于流场和声场的协同原理，开发了理论分析、实验测试和数值模拟方法，研究了膨胀管管段内的声能传递过程。