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Towards understanding effects of ultrasonic waves on subcooled boiling using particle image velocimetry
Ist Teil von
International communications in heat and mass transfer, 2024-08, Vol.156, p.107711, Article 107711
Ort / Verlag
Elsevier Ltd
Erscheinungsjahr
2024
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
In this study, effects of ultrasonic waves on heat transfer, bubble behavior and temporal variation of liquid flow near the heating surface in subcooled boiling was investigated with the help of high-speed particle image velocimetry method. Experimental results show that the enhancement effect of ultrasound on heat transfer and critical heat flux considerably depends on subcooling and boiling space height. In nucleate boiling regime, the ultrasound-induced acoustic streaming alters the upward liquid flow and changes the vortex structure associated with bubble growth, departure and rising. As heat flux increases, the bubble-induced convection accelerates and competes with the acoustic streaming near the heating surface, weakening the ultrasonic effect on heat transfer. In transition boiling regime, effects of ultrasonic waves on heat transfer of microbubble emission boiling depends on the competition between acoustic streaming and oscillating flow resulting from vapor film oscillation, with enhancement occurring when acoustic streaming dominates the liquid flow near the heating surface. Based on the visualization results, a scaling law is developed to determine the potential effects of ultrasound on critical heat flux.
•Effect of ultrasound on subcooled pool boiling was investigated using two-phase PIV.•Liquid flow near heating surface with and without ultrasound was studied.•Effect of ultrasound on MEB depends on both acoustic streaming and oscillating flow.•A scaling law was developed to determine the potential effect of ultrasound on CHF.