****************** **Vapor Pressure** ****************** :: Vapor Pressure = {model_name} {float_list} [varies] ----------------------- **Description / Usage** ----------------------- This required card is used to specify the model for the vapor pressure for each species; it has two main classes of use. The first class regards multiphase flow in porous media, which is activated when the media type is set to **POROUS_UNSATURATED** or **TWO_PHASE** (cf. the *Media Type* card). The second class of use of this data card is for specification of vapor pressure at the external boundary of a liquid domain, for which the bounding gas phase is modeled with a lumped parameter approach, or at an internal interface between a liquid and a gas. No curvature effects are included here. Eventually the models in this class will be supported in the porous-media cases. Definitions of the input parameters are as follows: +-----------------------+-------------------------------------------------------------------------------------+ |{model_name} |Name of the model for the vapor pressure, based on the class of use. | | | | | |For the first class of multiphase flows in porous media, {model_name} can be one of | | |the following: | | | | | | * **KELVIN** - for a volatile liquid | | | * **IDEAL_GAS** - for a non-condensable gas | | | * **FLAT** - for a volatile liquid | | | | | |For the second class regarding specification of vapor pressure at the external | | |boundary of a liquid domain or the interface between a gas and a liquid, {model_name}| | |can be one of the following: | | | | | | * **CONSTANT** - for a constant vapor pressure model | | | * **ANTOINE** - for temperature-dependent, nonideal gases | | | * **RIEDEL** -for temperature-dependent, nonideal gases | +-----------------------+-------------------------------------------------------------------------------------+ | |An integer designating the species equation. Typically this value is zero if the | | |problem is one of a single solvent in a partially saturated medium. | +-----------------------+-------------------------------------------------------------------------------------+ |{float_list} |One or more floating point numbers ( through ) whose values are | | |determined by the selection for {model_name}. | +-----------------------+-------------------------------------------------------------------------------------+ .. figure:: /figures/454_goma_physics.png :align: center :width: 90% Vapor pressure model choices and their parameters are discussed below. *Models in the first class...* +-----------------------+------------------------------------------------------------------------------------------+ |**KELVIN** |The for the **KELVIN** option specifies input values for seven parameters: | | | | | | * - Equilibrium vapor pressure across a flat interface | | | * - Liquid density | | | * - Molecular weight of the liquid | | | * - Gas law constant | | | * - Operating temperature | | | * - Molecular weight of air or gas phase | | | * - Ambient pressure of that gas phase | | | | | |The **KELVIN** option is used to include the effect of vapor-pressure lowering that | | |results in equilibrium over high curvature menisci, i.e., small pores. The equation form | | |of this is | +-----------------------+------------------------------------------------------------------------------------------+ |**FLAT** |The **FLAT** option requires the same seven parameters as the **KELVIN** model but leaves | | |off the exponential function, i.e., the vapor pressure is independent of the level of | | |capillary pressure. The constants are still needed so that the gas-phase concentration can| | |be calculated with the ideal gas law. See the **KELVIN** option above for definition of | | |the values. | +-----------------------+------------------------------------------------------------------------------------------+ |**IDEAL_GAS** |The for this model has three values, where: | | | | | | * - Molecular weight of the gas | | | * - Gas law constant | | | * - Operating temperature | +-----------------------+------------------------------------------------------------------------------------------+ *Models in the second class..* +-----------------------+------------------------------------------------------------------------------------------+ |**CONSTANT** |This model is used for a constant species source such as a homogeneous reaction term. The | | | has a single value: | | | | | | * - Vapor pressure | +-----------------------+------------------------------------------------------------------------------------------+ |**ANTOINE** |The **ANTOINE** model for vapor pressure is used in conjunction with the *VL_EQUIL* | | |boundary condition. If specified, a temperature-dependent vapor pressure for species i is | | |calculated. | | | | | |The model requires six values in the , where: | | | | | | * - A, the unit conversion factor for pressure based on the units in the | | | material file | | | * - Bi, Antoine coefficient for species i | | | * - Ci, Antoine coefficient for species i | | | * - Di, Antoine coefficient for species i | | | * - Tmin, Minimum temperature of the range over which the Antoine relation will | | | hold | | | * - Tmax, Maximum temperature of the range over which the Antoine relation will | | | hold | +-----------------------+------------------------------------------------------------------------------------------+ |**RIEDEL** |The **RIEDEL** model for vapor pressure is used in conjunction with the *VL_EQUIL* | | |boundary condition card. If specified, a temperature-dependent vapor pressure for species | | |i is calculated. | | | | | |The model requires eight values in the , where: | | | | | | * - A, the unit conversion factor for pressure based on the units in the | | | material file | | | * - Bi, Riedel constant for species i | | | * - Ci, Riedel constant for species i | | | * - Di, Riedel constant for species i | | | * - Ei, Riedel constant for species i | | | * - Fi, Riedel constant for species i | | | * - Tmin, Minimum temperature of the range over which the relation will hold | | | * - Tmax, Maximum temperature of the range over which the relation will hold | +-----------------------+------------------------------------------------------------------------------------------+ .. figure:: /figures/455_goma_physics.png :align: center :width: 90% .. figure:: /figures/456_goma_physics.png :align: center :width: 90% ------------ **Examples** ------------ An example use of the Antoine model for vapor pressure follows: :: Vapor Pressure = ANTOINE 0 1 9.380340229 3096.516433 -53.668 0.1 1000 ------------------------- **Technical Discussion** ------------------------- No Discussion. -------------- **References** -------------- No References.