EXPERIMENTAL STUDY OF THE INTENSIFICATION OF HEAT TRANSFER BY POOL BOILING LN2: APPLICATION TO COOLING OF A BRASS RIBBON IN HORIZONTAL POSITION

摘要

Boiling heat transfer process is important because it is a way to increase the flux density transmitted at low temperature differences. To quantify the thermal exchanges, we performed an experimental study of the nitrogen pool boiling, in transient conditions, on a horizontal brass ribbon for a fixed flux density. The results show that there is no break between the monophasic convection zone and the nucleated boiling region. In the nucleated boiling zone, the temperature variations are very small. We also note that the overheating required to trigger boiling increases with the time delay after the activation of nucleation sites.