The boiling characteristics of perforated plate-fin channels with liquid nitrogen in upflow

The boiling characteristics of liquid nitrogen in upflow in perforated-fin channels for plate-fin heat exchangers are identified. The measured local boiling coefficients have been obtained for process industry applications: mass fluxes from 37 to 120 kg/m/sup 2/s and pressures from 1.4 to 5.2 bar at low heat fluxes (less than 4000 W/m/sup 2/) where convective boiling was found to dominate. A two-phase film-flow model using a ''doublevelocity'' profile in the liquid film has been used to correlate with reasonable success the liquid film Nusselt number with the Reynolds number of the film and the Prandtl number of the liquid. A comparison with empirical methods of predicting convective boiling coefficients is presented.