ngas

    Noncondensible gas transport.

    • Group 1 - ICO2D
    • Group 2 - JA, JB, JC, PCO2
    • Group 3 - JA, JB, JC, CPNK
    • Group 4 - JA, JB, JC, QCD

    Note that all Group 2 values are entered first, followed by Group 3 values, followed by Group 4 values.

    Input Variable Format Default Description
    ICO2D integer 3
    Solution descriptor for noncondensible gas transport.
    ICO2D = 1, the 3 degree of freedom solution will be reduced to a 1 degree of freedom problem. (See macro iter, the parameter ICOUPL is also set to 5 if ICO2D = 1.)
    ICO2D = 2, the 3 degree of freedom solution will be reduced to a 2 degree of freedom problem. (See macro iter, the parameter ICOUPL is also set to 5 if ICO2D = 2.) ICO2D = 3, full 3 degree of freedom.
    PCO2 real
    Initial partial pressure of noncondensible gas. If PCO2 < 0 then ABS (PCO2) is interpreted as a temperature and the partial pressure of the noncondensible gas is calculated according to the formula:
    \(PCO2 = P_T - P_{SAT}(T)\)
    where \(P_T\) is the total pressure and \(P_{SAT}(T)\) is the water saturation pressure and is a function of temperature only.
    CPNK real
    If CPNK ≤ 0, then ABS (CPNK) is the specified noncondensible pressure and will be held at that value.
    If CPNK > 0, then CPNK is the specified relative humidity and the saturation, \(S_l\), is calculated using the vapor pressure lowering formula and the capillary pressure formula:
    \(Pcap(S_l) = \mathrm{ln}(h)\rho_l RT\)
    where \(Pcap\) is the capillary function, \(h\) is the humidity, \(R\) is the gas constant, \(T\) is the temperature, and \(\rho_l\) is the liquid density. Once the formula is solved, \(S_l\) is held constant. The humidity condition is only enabled for the van Genuchten capillary function model. See macro rlp.
    QCD real
    		Specified air source strength (kg/sec).

    The following is an example of ngas. In this example, a full 3 degrees of freedom solution is specified. The initial temperature at nodes 1 to 800 is 20 oC and the code is asked to calculate the initial noncondensible gas pressure. There is no specified noncondensible gas source.

    ngas      
    3      
    1 800 1 -20
           
    1 800 1
           
    1 800 1
           

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