7.7.4. POLY SHOM Input Format

This is an example of the minimum input required to convert a Shomate polynomial to Ansys Chemkin format; The Shomate equations are given in Equation 7–1 through Equation 7–3 , where t = Temperature(K)/1000. Parameters (A, B, C, D, E, F, G, and ΔH°f,298) can be obtained from the NIST Chemistry WebBook.[9]

  1. At the start of the NIST menu(http://webbook.nist.gov/chemistry/form-ser.html), choose calorie-based units in the toggle under question #3, when selecting the desired units for thermodynamic data.

  2. Perform a Formula Search (for example, search for OH).

  3. Highlight and copy the table of parameters (including the heading row and the rows for the A , B , C , D , E , F , G parameters), then paste these into a text file.

Defaults are PHAS=G, TMIN=298, TMAX=6000, and TEMP=1000 are obtained from the Shomate data, and H298 by an evaluation of the polynomial, but keywords may be used to supersede the defaults.

Figure 7.5: POLY SHOM Input File

SPEC OH
ELEM O 1
ELEM H 1
POLY SHOM 
Temperature (K) 298. - 1300. 1300. - 6000. 
A 7.714551 6.870701 
B -2.715801 1.126790 
C 3.251781 -0.194724 
D -0.919332 0.013085 
E -0.000319 -0.656747 
F 7.110691 6.313191 
G 53.91451 51.17510
END

(7–1)

(7–2)

(7–3)

A table of NPTS temperatures from TMIN to TMAX will be used to evaluate the properties; keywords NPTS or DELT may be used to modify this process.