Researchers Introduce Audible Sound Waves to Enhance Heat Transfer in Air Heat Exchangers

Strategic Insights -

Researchers at QILU University of Technology have found that introducing audible sound waves into an air heat exchanger can significantly reduce flow resistance and thermal resistance, thereby enhancing the heat transfer process. The team, led by Chang Guo, used a Collaborative Innovation Project of Colleges in Jinan, National Natural Science Foundation of China (NSFC), National Key Research & Development Program of China, and Natural Science Foundation of Shandong Province funding, published their findings in the Journal of Physics Research.

Key Takeaways:

  • The introduction of audible sound waves into an air heat exchanger can reduce flow resistance and thermal resistance, leading to improved heat transfer performance.
  • The sound waves induce oscillating flow, causing periodic fluctuation in velocity, while the temperature distribution remains stable.
  • The maximum velocity gradient layer exhibits distinct evolution characteristics across different surfaces, whereas the maximum temperature gradient layer remains stable.
  • The heat transfer characteristics are influenced by the combined effect of both gradient layers, with fluctuations in heat flux showing an inverse trend relative to those of the velocity gradient layer.
  • The time-averaged thicknesses of the velocity and temperature gradient layers in regions farther from the inlet decrease by more than 30% and 40%, respectively, as the sound pressure level increases from 0 to 140 dB.
  • The heat flux in these regions increases by over 30%, while that near the inlet remains largely unchanged.
  • The incidence of sound waves has minimal impact on heat transfer performance near the inlet but gradually enhances it along the flow direction.

Statistics:

  • The sound pressure level increased from 0 to 140 dB.
  • The time-averaged thicknesses of the velocity and temperature gradient layers decreased by more than 30% and 40%, respectively.
  • The heat flux in regions farther from the inlet increased by over 30%.
  • Additional authors for this research include Yinchen Li, Shenglong Zhang, Wei Wei, Can Ji, Zhigang Liu, and Ming Gao.

Sources:

  • Effect of Audible Sound Waves On the Evolution of Velocity and Temperature Gradient Layers Near the Heat Exchange Surface In an Air Heat Exchanger. Physics of Fluids, 2025;37(9).
  • Journal of Physics Research. 2025; p 238.
  • QILU University of Technology. (American Institute of Physics - www.aip.org/; Physics of Fluids - pof.aip.org/)
  • National Natural Science Foundation of China (NSFC)
  • National Key Research & Development Program of China
  • Natural Science Foundation of Shandong Province