Film boiling around a body of arbitrary shape in a porous medium.

Abstract

The two-phase boundary layer theory was adopted ot investigate subcooled free convection film boiling over a body of arbitrary shape embedded in a porous medium. A general similarity variable which accounts for the geometric effect on the boundary layer length scale was introduced to treat the problem once for all possible two-dimensional and axisymmetric bodies. By virtue of this generalized transformation, the set of governing equations and boundary conditions for an arbitrary shape reduces into the one for a vertical flat plate already solved by Cheng and Verma. Thus, the numerical values furnished for a flat plate may readily be translated for any particular body configuration of concern. Furthermore, an explicit Nusselt number expression, in terms of the parameters associated with the degrees of subcooling and superheating, has been established upon considering physical limiting conditions.