表面凝结UDF程序

Condensation UDF theory: Film condensation in the presence of noncondensable gases。 the UDF is based contains several assumptions: 1. Vapor phase contains a binary ideal gas mixture of air and water vapor 2. The liquid phase consists of only water 3. Local thermodynamic equilibrium exists at the liquid-vapor interface 4. Film condensation only is considered. Dropwise condensation does not take place 5. The thermal resistance of the liquid film is neglected.

/**************************************************/
/* User defined function source code for computing*/
/* condensation rate of water vapor at a surface  */
/* using surface reaction model                   */
/* B. Bell 4/5/00                                 */
/* Revision 11/2004                               */
/* Add underrelaxation to cold wall species b.c.  */
/* Revision 9/2003                                */
/* Remove extra code                              */
/* Replace text file with scheme variable for     */
/* source term underrelaxation factor             */
/* Revision 9/2003                                */
/* Fixed problem with if-then condition in        */
/* mixture_condensation macro                     */
/*                                                */
/* Revision 01/2003                               */
/* Modifying to be consistent for turbulent flow  */
/* as well as laminar flow                        */
/*                                                */
/* Revision 12/2001                               */
/* The revisions of 9/2001 basically consisted of */
/* replacing the surface reaction model with a    */
/* source term.  The idea was to be able to ensure*/
/* control over the wall mass fraction.  In doing */
/* so it is necessary to modify the source terms */
/* for the species equation and the continuity    */
/* equation so that when the diffusive flux of    */
/* species across the boundary is accounted for   */
/* the net amount of mass removed from the system */
/* will be the same as the net amount of h2o      */
/* removed from the system.                       */
/* This was not implemented properly in the pre-  */
/* vious revision so this is intended to implement*/
/* the model properly                             */
/*                                                */
/* Revision 9/2001                                */
/* Investigating effect of assumptions on mass    */
/* flux                                           */
/*                                                */
/* Revision 12/21/00                              */
/*                                                */
/* For post-processing heat flux is needed at wall*/
/* There will be a define on demand macro written */
/* where the heat flux at the wall is stored in   */
/* the face value of a user-defined memory loc.   */
/*                                                */
/* Revision 5/12/00                               */
/*                                                */
/* This revision uses User-defined scalars to     */
/* store the condensation rate information and    */
/* to compute the latent heat transfer rate at    */
/* the cold surface                               */
/*                                                */
/* Revised 4/14/00                                */
/*                                                */
/* Added adjust function “latent_heat“ which