Rewetting of hot surfaces-evaluation of wet region heat transfer coefficient from experimental data and prediction of rewetting velocity based on two-region model

The phenomenon of rewetting of hot surfaces is of significance in the context of emergency core cooling of water cooled nuclear reactors. Solutions have been obtained for conduction controlled rewetting of hot surfaces, based on two-region model, and these are correlated to relate Biot number and Peclet number and the non-dimensional temperature. Using these and the published data on rewetting velocity, wet region heat transfer coefficient values have been evaluated separately for falling film rewetting and bottom flooding rewetting. Based on these values correlations have been obtained for the wet region heat transfer coefficient by regression analysis. These correlations along with that for Peclet number have been used for predicting rewetting velocities. Reasonably good agreement is noted between the predicted values and experimental data