One-dimensional transient and steady-state models describing the process of material removal by vaporization and liquid expulsion using a concentrated heat source are developed and presented. Before melting occurs, the conduction has a known analytical similarity solution. This provides the initial temperature field for the melting problem. Before vaporization occurs, the heat transfer in liquid and solid phases is solved by moving boundary immobilization transformation so that the liquid and solid regions become fixed domains. When vaporization commences, there exists a discontinuity across the Knudsen layer of a few molecular mean free paths. This discontinuity is modeled by a Mott-Smith type solution. The vaporization process creates a recoil pressure which pushes the vapor away from the target and expels the liquid. The materials are, therefore, removed in both vapor and liquid phases. The materials removal rates are incorporated in the moving boundary immobilization transformation. The vapor phase is assumed to be optically thin so that its absorption of the high energy beam is negligible. Finite difference solution is obtained for the transient model. Closed form analytical solutions are obtained for the steady-state.
|Original language||English (US)|
|Number of pages||10|
|State||Published - 1987|
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