Numerical Simulation of Wave Formation and Heat Transfer inFalling Liquid Films at Unsteady Heat Release

The presented mathematical model enables calculation of the wave surface profile, as well as the fields of velocity and temperature, in falling wavy liquid films. Numerical simulation of wave formation and heat transfer intensity was performed for falling films of liquid nitrogen. Different activation functions for input perturbations were checked for films with different parameters. The dependencies of the time till boiling onset and total local evaporation time on the heat flux density were calculated for different inlet Reynolds numbers. Generalization of the simulation results resulted in a regime map, which describes different mechanisms of film flow decay. The presented results of numerical simulation are in satisfactory agreement with the experimental data.