eos

    Equation of State. Provide the code with alternate thermodynamic properties for the liquid and/or vapor phases. (This is one way in which the code may be instructed to simulate nonisothermal, single phase air. It may also be used to make comparisons between the code and analytical solutions that use different equations of state.)

    • Group 1 - IIEOSD, IPSAT, ITSAT
    • Group 2 - EWI, EW2, EW3, EW4, EW5, EW6, EW7, EW8, EW9, EW10, EW11
    • Group 3 - EVI, EV2, EV3, EV4, EV5, EV6, EV7, EV8, EV9, EV10, EV11

    For calculation of the simplified thermodynamic equations the above data is used to generate first order equations. The exception to this is the viscosity of the liquid and use of the ideal gas law. The viscosity of the liquid uses a 1/T term. For the calculation of vapor density and its derivatives, the ideal gas law is used instead of a linear relationship. Thus, EV4 and EV5 are not used, but are included so the format is the same as that for the liquid parameters in Group 2.

    Input Variable Format Description
    IIEOSD integer Equation of state reference number. When IIEOSD = 1 or 2 are used, they refer to the high and low pressure data sets, respectively, in FEHM. For these values the input in Group 2 and Group 3 will be ignored after it is entered. When any value other than 1 or 2 are used, the user-defined equation of state is used with Groups 2 and 3 for input.
    IPSAT integer Parameter to set vapor pressure to zero. If IPSAT ≠ 0 the vapor pressure is set to zero, otherwise the vapor pressure is calculated in the code.
    ITSAT integer Parameter to adjust the saturation temperature. If ITSAT < 0, the saturation temperature is set to -1000oC. If ITSAT > 0, the saturation temperature is set to 1000oC. If ITSAT = 0, the calculated value is used.
    EW1 real Liquid reference pressure (MPa).
    EW2 real Liquid reference temperature (oC).
    EW3 real Liquid reference density (kg/m3).
    EW4 real Derivative of liquid density with respect to pressure at reference conditions.
    EW5 real Derivative of liquid density with respect to temperature at reference conditions.
    EW6 real Liquid reference enthalpy (MJ/kg).
    EW7 real Derivative of liquid enthalpy with respect to pressure at reference conditions.
    EW8 real Derivative of liquid enthalpy with respect to temperature at reference conditions.
    EW9 real Liquid reference viscosity (Pa s).
    EW10 real Derivative of liquid viscosity with respect to pressure at reference conditions.
    EW11 real Derivative of liquid viscosity with respect to temperature at reference conditions.
    EV1 real Vapor reference pressure (MPa).
    EV2 real Vapor reference temperature (oC).
    EV3 real Vapor reference density (kg/m3).
    EV4 real Not used, included only to maintain a similar format to Group 2. Density variation with pressure governed by ideal gas law.
    EV5 real Not used, included only to maintain a similar format to Group 2. Density variation with temperature governed by ideal gas law.
    EV6 real Vapor reference enthalpy (MJ/kg).
    EV7 real Derivative of vapor enthalpy with respect to pressure at reference conditions.
    EV8 real Derivative of vapor enthalpy with respect to temperature at reference conditions.
    EV9 real Vapor reference viscosity (Pa s).
    EV10 real Derivative of vapor viscosity with respect to pressure at reference conditions.
    EV11 real Derivative of vapor viscosity with respect to temperature at reference conditions.

    The following is an example of eos.

    In this example, a user-defined equation of state is specified and the vapor pressure and saturation temperature are calculated in the code. For liquid properties, the reference pressure is \(0.1\:MPa\), the reference temperature is 20 °C, and the reference density is \(998.\:kg/m^3\), the derivative of density with respect to pressure is zero and with respect to temperature is \(-0.2\:kg/m^3/C\).

    The reference enthalpy is \(0.88\:MJ/kg\), the derivative of enthalpy with pressure is zero, and the derivative with temperature is \(4.2 \cdot 10^{-03}\:MJ/kg/C\).

    The reference viscosity is \(9 \cdot 10^{-04}\:Pa \cdot s\) and the derivatives of viscosity with pressure and temperature are zero.

    For vapor properties, the reference pressure is 0.1 MPa, the reference temperature is 20 oC, and the reference density is \(1.29\:kg/m^3\).

    The reference enthalpy is \(2.5\:MJ/kg\), the derivative of enthalpy with pressure is 0, and with temperature is \(0.1\:MJ/kg/C\).

    The reference viscosity is 2.e-4 Pa⋅s and its derivatives with pressure and temperature are zero.

    eos                    
    3 0 0                
    0.1
    		998
    		0.8
    		4.2e- 9.e-
    0.1
    		1.2
    		0 8
    		3 4
        9   . 2.5   0.1 2.e-    
            2       4    
           
    		           

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