Entropy and Exergy Analysis of Syngas Premixed Flames with a Detailed Mechanism

The entropy production (second law-based) and exergy loss analysis, from historical point of view, were
developed to evaluate and optimize the performance of energy conversion systems [1]. For those systems
involving a combustion process, it has been concluded that the major part of the exergy loss is due exactly
to the combustion process [1]. Therefore, entropy production has been investigated in several combustion
processes, for example: droplet combustion [2]; spray combustion [3]; coal/carbon combustion [4]; laminar
premixed flames [5, 6]; diffusion flames [7].
Four irreversible processes are responsible for entropy production during combustion: viscous dissipation,
heat conduction, mass diffusion, and chemical reaction [6]. The scope of this work is to study the local
entropy production due to these processes in premixed syngas laminar flames taking into account detailed
chemical kinetics and transport data. The effects of unburnt fuel mixture composition, equivalence ratio,
and inlet fluid temperature on local entropy generation are analyzed. Finally, the exergy loss ratio of each
process is evaluated with respect the exergy of the reactant fuel mixture.
References
[1] S. Som and A. Datta, "Thermodynamic irreversibilities and exergy balance in combustion processes,"
Progress in Energy and Combustion Science, vol. 34, no. 3, pp. 351-376, 2008.
[2] S. K. Dash and S. K. Som, "Transport processes and associated irreversibilities in droplet combustion
in a convective medium," International Journal of Energy Research, vol. 15, no. 7, pp. 603-619, 1991.
[3] A. Datta and S. Som, "Thermodynamic Irreversibilities and Second Law Analysis in a Spray Combustion
Process," Combustion Science and Technology, vol. 142, no. 1-6, pp. 29-54, 1999.
[4] S. K. Som, S. S. Mondal, and S. K. Dash, "Energy and Exergy Balance in the Process of Pulverized
Coal Combustion in a Tubular Combustor," Journal of Heat Transfer, vol. 127, no. 12, p. 1322, 2005.
[5] V. S. Arpaci and A. Selamet, "Entropy production in flames," Combustion and Flame, vol. 73, no. 3,
pp. 251-259, 1988.
[6] K. Nishida, T. Takagi, and S. Kinoshita, "Analysis of entropy generation and exergy loss during combustion,"
Proceedings of the Combustion Institute, vol. 29, no. 1, pp. 869-874, 2002.
[7] A. Datta, "Entropy Generation in a Confined Laminar Diffusion Flame," Combustion Science and Technology,
vol. 159, no. 1, pp. 39-56, 2000.