Default thermo-physical properties in combustion model

[DOGzym]

Hi all,
In User's guide I didn't find the default specific values ​​of the gas components in the combustion model. How are the default values ​​of these parameters determined in FDS?
And how to determine the thermo-physical properties of the combustion of substances(such as C5H8O2) that are not preset in the FDS defined by FORMULA?

[rmcdermo]

See Chapter 12 on Chemical Species. This points you to the Appendix and the references for properties are given there. If you specify a new species, I often use NIST webook.

[DOGzym]

Thanks for your suggestion!
In Appendix A of the User's Guide, I found some default parameters for the required gas-phase species.
Where do the default values ​​for more macroscopic and basic parameters (such as density, specific heat, thermal conductivity, etc.) that are not given in the table come from? I desperately need reference sources for these parameters.

[drjfloyd]

Per the Technical Reference Guide density is via the equation of state.

Per the User's Guide Chapter 12 thermal conductivity uses Lenard Jones parametesr and specific heat uses NASA polynomials. Look at the references listed for Appendix A:

[96] B. McBride, S. Gordon, and M. Reno. Coefficienes for Calculating Thermodynamic and Transport
Properties of Individual Species. NASA Technical Memorandum 4513, National Aeronautics and
Space Administration, Cleveland, OH, 1993. 490, 491
[97] B. McBride, M. Zehe, and S. Gordon. NASA Glenn Coefficienes for Calculating Thermodynamic
Properties of Individual Species. NASA/TP 2002-211556, National Aeronautics and Space Administration,
Cleveland, OH, September 2002. 490, 491
[98] R. Svhela. Estimated Viscosities and Thermal Conductivity of Gases at High Temperatures. NASA
Technical Report R-132, National Aeronautics and Space Administration, Cleveland, OH, 1962. 490,
491
[99] M.W. Chase. NIST-JANAF Thermochemical Tables. Journal of Physical and Chemical Reference
Data, Monograph No. 9. American Chemical Society, Woodbury, New York, 4th edition, 1998. 490,
491
[100] A. Faghri and Y. Zhang. Transport Phenomena in Multiphase Systems. Academic Press, Cambridge,
MA, 1st edition, 2006. 490, 491
[101] J.E. Hardy, J.O. Hylton, and T.E. McKnight. Empirical Correlations for Thermal Flowmeters Covering
a Wide Range of Thermal-Physical Properties. In National Conference of Standards labs (NCSL)
1999 Workshop and Symposium, 1999. Charlotte, North Carolina. 490, 491
[102] I. Martiez. Termodinamica Basica y Aplicada. Dossat, Editorial S.A., Madrid, Spain, 1992. 490, 491
487

[DOGzym]

Thank you for your reply!

In addition to the common gas species which are predefined in FDS, my pyrolysis and combustion model involves the pyrolysis product MMA (C5H8O2), which is not predefined in FDS. I only defined its chemical formula and HEAT_OF_COMBUSTION for MMA.

What impact will this have on the accurate simulation of the combustion process of MMA?

In the gas phase combustion model of FDS, is it necessary to define the thermo-physical parameters of gas species such as MMA that are not predefined?

[rmcdermo]

This is to broad a question. As a user, you should understand the physical approximations in your model.