Solid-Liquid-Gas Systems

Abstract

In this chapter, the liquid-gas, two-phase flow, and heat transfer—including the evaporation/condensation phase change—around solid surfaces are considered. Temperature and velocity nonuniformities are allowed in the liquid and gas phases, and all three phases are in thermal nonequilibrium. The heat flows across the phase interfaces, and mass transfer (evaporation/condensation) occurs across the liquid-gas interface. The liquid and the gas can be multicomponent mixtures. Chart 8.1 lists the various fluid, solid surface, and flow variables affecting the evaporation and condensation rate and the solid surface temperature, in heat transfer across a solid surface with liquid/vapor phase change. Throughout this chapter these variables will be discussed. We begin with a more general classification. Chart 8.2 gives a classification of the nonisothermal liquid-gas two-phase flow and heat transfer (including phase change) around solid surfaces. In some applications only one fluid phase is in contact with the solid and the liquid-gas interface is continuous, as in the vapor or liquid films. In others, both liquid and gas are in contact with the surface, as in surface bubble and droplet nucleation and in droplet impingement on heated surfaces. The solid-liquid-gas contact line is also called the common line or interline, as discussed in Section 1.4.4(C). In the following the flow and heat transfer in the vapor and liquid films covering solid surfaces are considered first.