A Study of Entropy Generation in Coflow Diffusion Flames Fueled by Liquefied Petroleum Gas

This work reports the entropy generation in coflow diffusion flames fueled by liquefied petroleum gas (LPG). In the coflow configuration, LPG flows through a centrally located core tube and air is supplied through the surrounding annular portion. The coflow air is systematically increased from 100 to 400% of the required stoichiometric value. Similarly, primary air is gradually varied from 10 to 50% of the stoichiometric value. The burner is operated at 250 W. Entropy generation during heat and mass transport processes, and chemical reactions are calculated for each flame. The entropy generation in the process of heat transfer is calculated using temperature gradients. The entropy generation during chemical reactions is calculated as the product of chemical potential and net reaction rates of chemical species. The net reaction rates are calculated using a detailed kinetics mechanism consisting of 43 species and 396 elementary reactions. The entropy generation in the process of mass diffusion is calculated using diffusion coefficient and species gradients. The various modes of entropy generation are calculated using an inhouse MATLAB code. The total entropy generation is plotted as a function of primary and coflow air for these cases. Further, entropy fields are plotted to show the location and distribution of entropy generation in these flames.