Heat Transfer Efficiency of Turbulent Film Boiling on a Horizontal Elliptical Tube with External Flowing Liquid

Abstract

Film boiling on a horizontal elliptical tube immersed in external flowing nitrogen liquid is inves-tigated in the present paper. The isothermal wall temperature is high enough to induce turbulent film boiling, and then a continuous vapor film runs upward over the surface. The high velocity of the flowing saturated liquid at the boundary layer is determined by potential flow theory. In addi-tion, the present paper addresses a new model to predict the vapor-liquid interfacial shear on an elliptical tube under forced convection turbulent film boiling. In the results, film thickness and Nusselt number can be obtained under different eccentricity and Froude number. And a compari-son between the results of the present study and those reported in previous experimental studies is provided. The results show that there is a good agreement between the present paper and the experimental data.