The effect of mechanical vibrations on heat transfer during nucleate boiling at different pressures
D.V. Kuznetsov1,2, I.A. I.A. Kosovskikh1,2, O.A. Volodin1, I.M. Serdyuk3, V.S. Serdyukov1,2,3
1Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
3Chinakal Institute of Mining SB RAS, Novosibirsk, Russia
Keywords: boiling, heat transfer, vaporization, active methods of heat transfer intensification, vibration exposure
Abstract
The article presents the results of an experimental study of the effect of mechanical vibration on heat transfer and vaporization dynamics during nucleate boiling of saturated water in the pressure range of 10-101.3 kPa. The relevance of the study is determined by the need to improve heat transfer efficiency in power and thermal engineering systems operating under reduced pressure and subject to external mechanical influences. Despite the existence of numerous studies devoted to boiling at atmospheric pressure, the effect of vibrations at reduced pressures remains insufficiently studied. This study demonstrates that applying vibration to a liquid leads to an earlier onset of boiling, a reduction in heating surface superheat, and an increase in heat flux at a fixed superheat. The most pronounced effect is observed at lower pressures, whereas at atmospheric pressure, the influence of vibration is weakened and manifests itself primarily in the region of initial nucleate boiling. Analysis of video data revealed that vibration exposure leads to a decrease in the bubble separation diameter, an increase in the frequency of bubble separation, and an increase in the density of active vaporization sites, especially at low pressures. The obtained results confirm that mechanical vibration is an effective active method for controlling boiling processes and can be used in the development and optimization of thermal engineering systems operating over a wide pressure range.
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