Thermodynamic property models for unburned mixtures and combustion gases

New mathematical functions, with the functional form of a fifth order logarithmic polynomial, have been developed. These polynomials have been used to describe gases' thermodynamic properties, and have been utilized for combustion processes, with frozen composition and shifting equilibrium composition evaluation. The logarithmic polynomials present the advantage of covering a wide range of temperatures with only a single mathematical function. The logarithmic polynomial coefficients have been evaluated through the least squares fit on the basis of experimental measurements (taken from scientific literature). The set of logarithmic polynomials gives the possibility of studying the combustion phenomena and allows for the description of specific heat at constant pressure, enthalpy, entropy and equilibrium constants for gases' dissociation.