Investigation on the Acoustic Energy Transfer Process in Expanded Pipe of Heat Exchangers

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.