.FCSys.Characteristics.BaseClasses.Characteristic

Information

This package is compatible with NASA CEA thermodynamic data [McBride2002] and the virial equation of state [Dymond2002].

Notes regarding the constants:

• Currently, formula may not contain parentheses or brackets.
• d is the Van der Waals diameter or the diameter for the rigid-sphere ("billiard-ball") approximation of the kinetic theory of gases [Present1958].
• b_c: The rows give the coefficients for the temperature intervals bounded by the values in T_{lim c}. The powers of T increase by column. By default, the powers of T for the first column are each -2, which corresponds to [McBride2002]. In that case, the dimensionalities of the coefficients are {L4.M2/(N2.T4), L2.M/(N.T2), 1, …} for each row, where L is length, M is mass, N is particle number, and T is time. (In FCSys, temperature is a potential with dimension L2.M/(N.T2); see the Units package.)
• B_c: As in b_c, the rows correspond to different temperature intervals. The first column is for specific enthalpy and has dimensionality L2.M/(N.T2). The second is for specific entropy and is dimensionless. The integration constants for enthalpy are defined such that the enthalpy at 25 °C is the specific enthalpy of formation at that temperature and reference pressure [McBride2002, p. 2]. The integration constants for specific entropy are defined such that specific entropy is absolute.
• T_{lim c}: The first and last entries are the minimum and maximum valid temperatures. The intermediate entries are the thresholds between rows of b_c (and B_c). Therefore, if there are n temperature intervals (and rows in b_c and B_c), then T_{lim c} must have n + 1 entries.
• The reference pressure is p^o. In the NASA CEA data [McBride2002], it is 1 bar for gases and 1 atm for condensed species. For gases, the reference state is the ideal gas at p^o. For example, the enthalpy of a non-ideal (real) gas at 25 °C and p^o with ReferenceEnthalpy.zeroAt25degC is not exactly zero.
• If the material is gaseous (phase == Phase.gas), then the first virial coefficient must be independent of temperature. Otherwise, the function for specific enthalpy (h) will be ill-posed. Typically, the first virial coefficient is one (or equivalently U.R), which satisfies this requirement.

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