Cpo(Ideal Gas)

  • DEFAULT 1: Wilhoit Equation: (Output details)
    Cpo / R = a0 + (a1/T 2) × exp(-a2 /T ) + a3 ×y2 + {a4 - a5 /(T - a7)2}×y 8
    where R is the gas constant. If T is greater than a7, then y = (T - a7)/(T + a6). If T is less than or = a7, then y = 0.

    See Thermodynamics of Organic Compounds in the Gas State (Volumes I and II) by M. Frenkel, G. J. Kabo, K. N. Marsh, G. N. Roganov, and R. C. Wilhoit. Published by the Thermodynamics Research Center (TRC), College Station: TX. 1994.

  • DEFAULT 2: PolynomialHC: (Output details)
    Cpo = å ai

    × T i, where the summation is from i = 0 to nTerms - 1.

  • Alternative 1: Yaws.PolynomialExpansion (Output details)
    Cpo = å ai

    × T i, where the summation is from i = 0 to nTerms - 1.

  • Alternative 2: AlyLee (which is also DIPPR 107) (Output details)

    Cpo = a + b×{(c/T)/sinh(c/T)}2 + d×{(e/T)/cosh(e/T)}2

  • Alternative 3: PPDS2 (Output details)
    Cpo/R = Clow + (C ¥ - Clow) ×y2 ×{1 + (y - 1) å(ai × yi)} ; where the summation is from i = 0 to 4.

    Clow and C ¥ are equation constants, and y = T / (T + TS), where TS is a constant.

  • Alternative 4: Helmholtz (Output details)
    Cpo/R = 1 + t - {åai ×ni ×(ni - 1)× tni}(ni ¹ 0 or 1) + åbi ×(ci × t)2 ×exp(ci × t) / {exp(ci × t) - 1}2;

    where t = Tc/T, Tc = the critical temperature, R is the gas constant, and the summations are from i = 1 to nTerms.

  • Alternative 5: Yaws.HighIG (Output details) for high-temperature applications
    Cpo = å ai × T n(i) , where the summation is from i = 1 to 4.