Shape Change of an Initially Vertical Wall Undergoing Condensation-Driven Melting

Condensation-driven melting of an initially vertical wall is studied both analytically and experimentally. It is shown that a vertical surface undergoing simultaneous melting-condensation will not stay vertical and will go through a series of transient shapes before attaining a steady-state shape. Numerical solutions are obtained both for the transient shapes of the wall and the heat transfer. The steady-state shape of the wall is found to be the one which yields a constant melting rate along the wall. The total melting rate is shown to increase during the time the shape change occurs such that the steady-state shape yields about 35 percent more melting rate than the initial vertical wall. Experiments are conducted at one atmosphere pressure by condensing saturated steam on vertical surfaces of slabs made of naphthalene, biphenyl, and stearic acid. The heat transfer and shape change data are found to compare well with the predictions.