******************** **Molecular Weight** ******************** :: Molecular Weight = CONSTANT ----------------------- **Description / Usage** ----------------------- This card specifies the molecular weight of a species. It is required when the Stefan- Maxwell flux model is used in modeling multicomponent transport of neutral or charged species. It is also required when vapor-liquid phase equilibrium is considered at the material boundaries. Molecular weight is used to convert units of mass fraction to mole fraction in a species material balance. +--------------------------+-------------------------------------------------------------------------------------+ |**CONSTANT** |Molecular weight model type. | | | | | | * - species number | | | * - molecular weight of the species | +--------------------------+-------------------------------------------------------------------------------------+ ------------ **Examples** ------------ The following is a sample input card: :: Molecular Weight = CONSTANT 0 6.939 ------------------------- **Technical Discussion** ------------------------- This card originated from the development of a multicomponent diffusion model based on the Stefan-Maxwell equation. However, it has been generalized to include problems where mole fractions are necessary for the consideration of phase equilibria. For example, when *YFLUX_EQUIL* is invoked in the input deck, an equilibrium problem is solved rigorously which requires gas and liquid mole fractions. The conversion from mass fraction to mole fraction requires molecular weight information. -------------- **References** -------------- No References.