Combustion thermodynamics

Modem computational programs [4] and thermodynamic tables [5] now make it possible to explicitly calculate metal-oxygen flame temperatures, thereby opening up a unique aspect of combustion thermodynamics that could be important in the consideration of metal as fuels and as reactants in combustion synthesis. 

Corresponding to these three problems our paper is divided into three parts. In the first (Sections 3-6) is set forth the experimental material on the amount of nitric oxide formed in explosions of mixtures of various combustibles with oxygen and nitrogen. It is shown that heating the mixture is equivalent to adding a corresponding amount of combustible. Thermodynamic computations show that in all cases the observed amount of nitric oxide is less than the equilibrium value at the maximum temperature of the gas. Direct experiments on the combustion of a gas in a stream have proved that the nitric oxide is not formed during but only after combustion. Thus, in Part I the thermal nature of the reaction is proved. 

Heat of Combustion. Thermodynamics allow calculation of the heat of combustion, htP, as the difference between the free energy of the products and reactants in equation 4. Additive molar contributions to the free energy of gaseous, liquid, and solid fuels have been tabulated and used successfully to estimate heats of combustion. A simpler method for calculating or measuring combustion heat is based on the observation that the net heat of complete combustion of organic fuels per mole of oxygen consumed is independent of the chemical composition of the fuel (20),... 

The difference in particle size, using different fuels, depends on the number of moles of gaseous products released during combustion. Thermodynamic modeling shows an increase in gas generation with an increase of the fuel-oxidant. 

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