Theoretical modeling of rapid surface vaporization with backpressure
Abstract
In this paper a theoretical model is developed for rapid surface vaporization into a surrounding ambient atmosphere. The primary emphasis is on metallic surfaces. Power input levels are taken to be low enough so that thermodynamic equilibrium can be assumed before phase change to gas. At high evaporation rates there will be a narrow Knudsen layer region in the gaseous flow just outside the phase interface in which translational nonequilibrium prevails. The modeling treats this layer as a gasdynamic discontinuity and approximate jump conditions are derived. The flow Mach number just outside the Knudsen layer is dictated by the state well away from the surface. Its determination is discussed both for a simple model of transient flow induced by a laser pulse and for the general case of timevarying power input. Examples assume the metallic surface is aluminum and the surrounding air pressure ranges from 1 atm to hard vacuum.
 Publication:

11th Fluid and Plasma Dynamics Conference
 Pub Date:
 July 1978
 Bibcode:
 1978fpdy.confR....K
 Keywords:

 Evaporation Rate;
 Laser Heating;
 Mathematical Models;
 Metal Surfaces;
 Pressure Effects;
 Gas Dynamics;
 Knudsen Flow;
 LiquidVapor Interfaces;
 Metal Vapors;
 Pulsed Lasers;
 Surface Reactions;
 Vaporizing;
 Fluid Mechanics and Heat Transfer