Film boiling heat transfer from a horizontal circular plate facing downward

Abstract

The two-dimensional, steady, pool film boiling heat transfer from a horizontal circular plate facing downward to a stagnant saturated liquid is studied theoretically. It is assumed that the vapor-liquid interface is smooth and that radiation can be disregarded. The relevant governing equations for the vapor film are solved for saturated water at atmospheric pressure using an improved two-equation boundarylayer integral method. It is shown that the dimensionless temperature profile is affected by the wall superheat ∆T sat and that the ratio of Nu to X 0.2 is an increasing function of ∆T sat . Here, Nu represents the mean Nusselt number and X the film-boiling Rayleigh number. In addition, it is revealed that the one-equation boundary-layer integral method developed by Nishio and colleagues is fairly accurate in predicting the film thickness, the representative radial velocity, and the mean Nusselt number.