Numerical simulation of laminar film boiling heat transfer from vertically suspended smooth surfaces in cryogenic fluids subjected to constant wall heat flux

摘要

This study is aimed at solving the one-field conservation of mass, momentum, and energy equations for laminar film boiling from vertically suspended smooth surfaces in cryogenic fluids subjected to constant wall heat flux boundary condition. Solutions to the problem of laminar film boiling under constant wall temperature boundary condition have been obtained in the past using analytical and iterative technqies. Here, the governing equations are solved under constant heat flux boundary condition using an analyical method supplemented with curve fitting technqiues. The procedure is iterative because it assumes the vapor film thickness to start the calculations and then uses the energy equation at the interface to check the accuracy of this assumption. A computer program was developed to integrate this iterative procedure with a scheme that respeats the calculations at different discrete locations along the heated surface to estimate the laminar film thickness and to generate the velocity and the temperature profiles within the film boundary. The numerical results are compared to the experimental results for a stainless steel plate vertically suspended in liquid nitrogen where the plate is heated by constant current. The numerical predictions are matched with the experimental results by using a calibration parameter that reslates various properties of the liquid and the vapor.