Abstract

FYGUEROA-SALGADO, Simón Jesús; SERRANO-RICO, Juan Carlos  and  MOLINA-MOJICA, José Rodolfo. A Method to Determine the Thermodynamic Properties of Fuel Mixtures Considering Twelve Chemical Species in the Products. Ing. Univ. [online]. 2012, vol.16, n.1, pp.59-75. ISSN 0123-2126.

This article describes a method to determine theoretically the equilibrium composition, the thermodynamic properties and the adiabatic flame temperature of the combustion products of a fuel-air mixture taking into consideration that reactive products include twelve chemical species. It considers that fuel is an oxygenated hydrocarbon and that air is composed of oxygen, nitrogen and argon. By applying mass conservation and chemical balance conditions to the combustion reaction, this yields a closed algebraic system of equations which is linearized by using the Taylor series expansion and solved by using the Gauss pivoting elimination method. The described method allows the theoretical analysis of the combustion process that occurs in reciprocating internal combustion engines. The results obtained by applying the method to the combustion of ethyl alcohol (C₂H₆O), and by using the developed software, show that the NO concentration decreases with an increasing equivalence ratio, while the H₂O, the H₂ and the CO concentration increases when increasing such ratio, and that the adiabatic flame temperature reaches its maximum when the ratio is slightly higher than the stoichiometric one.

Keywords : Thermodynamic properties; combustion gases - mensuration; chemical equilibrium.

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