The main aim of this work is to investigate experimentally the influence of ultrasonic waves, on the heat transfer enhancement, from a stainless steel circular cylinder to distilled water, in subcooled boiling conditions. This study has carried on for a few years at the Department of Energetics "L.Poggi". The effect was observed since '60s: different authors had investigated the cooling effect due to the ultrasonic waves at different heat transfer regimes, especially from a thin platinum wire to water. They had found out that the highest heat transfer coefficient enhancement was been in subcooled boiling conditions. So this paper has the purpose to clarify the physical phenomenon and optimize a large range of variables involved in the mechanism. It reports the experimental results obtained with ultrasound at the frequency of 38 kHz, at two different subcooling degrees, Delta T-SUB = 25 and 35 degrees C. The heat fluxes applied on the cylinder, the ultrasonic generator power, P-gen and also the placement of the heater inside the ultrasonic generator tank, are been varied. The ultrasonic waves seem to be very useful for a practical application in the last generation electronic components cooling: they need dissipating huge heat fluxes and avoiding high temperatures (approximate to 150 degrees C), after that they could damage themselves.
Heat transfer enhancement from a circular cylinder to distilled water by ultrasonic waves at different subcooling degrees
BARTOLI, CARLO
2010-01-01
Abstract
The main aim of this work is to investigate experimentally the influence of ultrasonic waves, on the heat transfer enhancement, from a stainless steel circular cylinder to distilled water, in subcooled boiling conditions. This study has carried on for a few years at the Department of Energetics "L.Poggi". The effect was observed since '60s: different authors had investigated the cooling effect due to the ultrasonic waves at different heat transfer regimes, especially from a thin platinum wire to water. They had found out that the highest heat transfer coefficient enhancement was been in subcooled boiling conditions. So this paper has the purpose to clarify the physical phenomenon and optimize a large range of variables involved in the mechanism. It reports the experimental results obtained with ultrasound at the frequency of 38 kHz, at two different subcooling degrees, Delta T-SUB = 25 and 35 degrees C. The heat fluxes applied on the cylinder, the ultrasonic generator power, P-gen and also the placement of the heater inside the ultrasonic generator tank, are been varied. The ultrasonic waves seem to be very useful for a practical application in the last generation electronic components cooling: they need dissipating huge heat fluxes and avoiding high temperatures (approximate to 150 degrees C), after that they could damage themselves.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
