Thermodynamics of Combustion

Abstract

Although combustion processes often involve chemical reactions that may be far from equilibrium, the equilibrium state provides a useful guide on the ultimate combustion state if sufficient time is given. Chemical compositions of the combustion products at equilibrium, heating value of a fuel, and flame temperature can be determined from thermodynamics. In comparison to the thermodynamics of a pure substance, the thermodynamics of combustion systems are complicated by the change of components during combustion. That is, the components in the final state are different from those in the initial state. With the introduction of enthalpy of formation, the general approach normally used to solve thermodynamic problems of a pure substance can be extended to combustion systems. The following topics will be discussed in this chapter: (1) properties of mixtures, (2) combustion stoichiometry, (3) heating values and enthalpy of formation, (4) adiabatic flame temperatures, and (5) equilibrium state (Cantera Program).