POOL BOILING ON MULTIPLE SURFACES IN PROXIMITY

摘要

Information on the boiling heat transfer on a surface when affected by the presence of other surfaces is scares. Pool boiling heat transfer process on multiple surfaces in proximity has been investigated in this work. In particular, the boiling curve and the critical heat flux on a surface located in the heated plume of another surface is studied experimentally. The surfaces are made of two identical wires with known diameter positioned horizontally in a predetermined short distance from each other. Tests were performed by heating the wires up to the critical heat flux in a pool of stationary FC-72 fluid. The boiling curves were experimentally developed for a surface when it is located in the plume of another heated surface. Initial results indicate that the critical heat flux on such a surface drops more than 30% compared to a single isolated wire. The change may be attributed to the plume effects on the bubble formation and bubble dynamics of upper surface as well as the effects on the degree of subcooling in the immediate neighborhood of the test surface. The research focused on the effects of spacing and the degree of subcooling on the boiling and the critical heat flux of the upper surface which is affected by the natural convection and boiling plume of the lower surface. The results of this project are expected to expand the existing knowledge of boiling heat transfer, particularly when it is affected by the presence of other surfaces in the proximity.