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- The NASA thermo data file format was documented in:
-
- Sanford Gordon and Bonnie J. McBride, "Computer Program for Calculation of
- Complex Chemical Equilibrium Compositions and Applications: I. Analysis",
- NASA Reference Publication 1311, October 1994.
-
- Bonnie J. McBride and Sanford Gordon, "Computer Program for Calculation of
- Complex Chemical Equilibrium Compositions and Applications: II. Users Manual
- and Program Description", NASA Reference Publication 1311, June 1996.
-
- The equations below for nondimensional specific heat, enthalpy, and
- entropy, are given in Sanford and Bonnie (1994). Eqs. 4.6-4.8 are the
- "old" NASA format, and Eqs. 4.9-4.11 are the "new" NASA format as discussed
- in this file.
-
- Eq. 4.6: Cp0/R = a1 + a2*T + a3*T^2 + a4*T^3 + a5*T^4
- Eq. 4.7: H0/RT = a1 + a2/2*T + a3/3*T^2 + a4/4*T^3 + a5/5*T^4 + a6/T
- Eq. 4.8: S0/R = a1*ln(T) + a2*T + a3/2*T^2 + a4/3*T^3 + a5/4*T^4 + a7
-
- Eq. 4.9: Cp0/R = a1*T^-2 + a2*T^-1 + a3 + a4*T + a5*T^2 + a6*T^3 + a7*T^4
- Eq. 4.10: H0/RT = -a1*T^-2 + a2*T^-1*ln(T) + a3 + a4*T/2 + a5*T^2/3 +
- a6*T^3/4 + a7*T^4/5 + b1/T
- Eq. 4.11: S0/R = -a1*T^-2/2 - a2*T^-1 + a3*ln(T) + a4*T + a5*T^2/2 +
- a6*T^3/6 + a7*T^4/4 + b2
-
- The following information is quoted directly from McBride and Gordon (1996):
-
- "Appendix A: Format for Thermodynamic Data
-
- The library of thermodynamic data contains data for both reaction products
- and reactants. All reaction products and some reactants are in the
- nine-constant functional form discussed in section 4.2 of Gordon and
- McBride (1994). The format for these data is given here. Thermodynamic
- data are provided with the program on a separate file, thermo.inp.
- Sections 2.8 and 5.24 discuss the processing of the thermo.inp data and
- the storing of the processed data in thermo.lib for subsequent use in the
- CEA program. Names of species contained in thermo.inp are listed in
- Appendix B.
-
- The general format is given in table A1. This format is applicable for
- all gaseous species and for those condensed species whose data extend over
- a temperature range. For those condensed species with data given at only
- one temperature, the format is somewhat different. On record 2, instead
- of the last number being a heat of formation, it is an assigned enthalpy.
- (Note that if the temperature is 298.15 K, the heat of formation and the
- assigned enthalpy are equivalent.) The first number in record 2 (number
- of temperature intervals) is always zero. On record 3, only one number is
- given, the temperature of the assigned enthalpy on record 2. Two examples are
- given. Example A1, for chlorine gas, illustrates the general format.
- Example A2, for liquid acetylene, illustrates the format for a condensed
- species with data given at only one temperature. The general equations
- for dimensionless heat capacity, enthalpy, and entropy (eqs. (4.6) to (4.8)
- <sic> from Gordon and McBride, 1994) are repeated for convenience.
-
- Record Constants Format Column
- 1 Species name or formula A24 1 to 24
- Comments (data source) A56 25-80
- 2 Number of T intervals I2 2
- Optional identification code A6 4-9
- Chemical formulas, symbols, and numbers 5(A2,F6.2) 11-50
- Zero for gas and nonzero for condensed phases I1 52
- Molecular weight F13.5 53-65
- Heat of formation at 298.15 K, J/mol F13.5 66-80
- 3 Temperature range 2F10.3 2-21
- Number of coefficients for Cp0/R I1 23
- T exponents in empirical equation for Cp0/R 8F5.1 24-63
- {H0(298.15)-H0(0)}, J/mol F15.3 66-80
- 4 First five coefficients for Cp0/R 5D16.8 1-80
- 5 Last three coefficients for Cp0/R 3D16.8 1-48
- Integration constants b1 and b2 2D16.8 49-80
- ... Repeat 3, 4, and 5 for each interval
-
- Example A.1:
-
- CL2 Chlorine gas. TPIS 1989, v1, pt2, p88.
- 2 tpis89 CL 2.00 0.00 0.00 0.00 0.00 0 70.90540 0.000
- 200.000 1000.000 7 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 0.0 9181.110
- 3.46281724D+04 -5.54712949D+02 6.20759103D+00 -2.98963673D-03 3.17303416D-06
- -1.79363467D-09 4.26005863D-13 0.00000000D+00 1.53407075D+03 -9.43835303D+00
- 1000.000 6000.000 7 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 0.0 9181.110
- 6.09256675D+06 -1.94962688D+04 2.85453491D+01 -1.44996828D-02 4.46388943D-06
- -6.35852403D-10 3.32735931D-14 0.00000000D+00 1.21211722D+05 -1.69077832D+02
-
- Empirical equations for example A.1:
-
- Heat capacity: Cp0/R = a1*T^-2 + a2*T^-1 + a3 + a4*T + a5*T^2 + a6*T^3 + a7*T^4
- Enthalpy: H0(T)/(RT) = -a1*T^-2 + a2*T^-1*ln(T) + a3 + a4*T/2 + a5*T^2/3 +
- a6*T^3/4 + a7*T^4/5 + b1/T
- Entropy: S0(T)/R = -a1*T^-2/2 - a2*T^-1 + a3*ln(T) + a4*T + a5*T^2/2 +
- at*T^3/3 + a7*T^4/4 + b2
-
- Example A.2:
-
- C2H2(L),acetyle Acetylene. JANAF Prop.Ser.E,1/67. TRC a-3000,10/86.
- 0 1 3/95 C 2.00H 2.00 0.00 0.00 0.00 1 26.03788 207599.000
- 192.35"
-
- Notes:
- 1. Besides a very different file layout, the most significant change between
- the older (1971) NASA thermo data and the 1996 data is the generalization
- to any number of temperature intervals.
- 2. The preceding discussion only mentions the format of individual species
- data blocks. In addition, the thermo input file included with the NASA
- CEA program contains:
- a. Comments at the top of the file marked by exclamation (!) points in the
- first column
- b. Two lines at the beginning of the species data:
- i. One line containing only "thermo"
- ii. One line with 4 temperatures and a date
- c. A line containing only "END PRODUCTS" separating product species from
- reactants, and a line at the end of the file containing only
- "END REACTANTS".
- 3. There are some differences between the format actually used by CEA and
- the format described in McBride and Gordon (1996), and some undocumented
- features:
- a. In the CEA code, the actual read and format statements differ from the
- documentation by:
- i. The species name on the first line of a block is 15 characters long,
- not 24. The rest of the line is comments.
- ii. The heat of formation at the end of line 2 is read with f15.3, not f13.5
- iii. The temperature range at the beginning of line 3 is read as 2F11.3,
- not 2F10.3.
- iv. Line 5 is formatted as 2D16.8,16x,2D16.8 rather than
- 3D16.8,2D16.8. The 16x acknowledges that the third field is
- not actually used. The first two fields are the 6th and 7th
- polynomial coefficients, and the last two fields are the 8th and
- 9th (integration constants).
- b. Although the number of polynomial coefficients is included in the data,
- this number is almost always 7 (plus 2 integration constants). In the
- current NASA database, there are only 3 species that use less than
- 7 coefficients (P4O10(cr), P4O10(cr), and P4O10(L)). Apparently if
- less than 7 are used, they are the lowest numbered (a1, a2, a3, ...).
- 4. In the preceding excerpt from McBride and Gordon (1996), reference is
- made to eqs. (4.6) to (4.8). These should be eqs. (4.9) to (4.11).
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