“HEAT TRANSFER ENHANCEMENT FROM A CIRCULAR CYLINDER TO DISTILLED WATER BY ULTRASONIC WAVES: PRELIMINARY REMARKS”

An experimental investigation was carried out to research the effects of ultrasonic waves on heat transfer, in subcooled boiling conditions, from a stainless steel horizontal cylinder, heated by Joule effect, to distilled water. Actually the acoustical streaming induces turbulence through the cinematic field and so an increase of the heat transfer coefficient. In this preliminary paper, the authors have studied the heat transfer enhancement for two-phase conditions. The dependence on such parameters as ultrasonic wave power, subcooled ΔT and convection heat flux is also examined. The aim of this paper is to find out the parameters that maximise the heat transfer coefficient. After our preliminary tests we had found that the maximum heat transfer coefficient increase occurs at the difference between the water saturation temperature and prefixed water temperature is higher, as also the ultrasonic generator power