ABSTRACT
The combustion process in hydrocarbon fuels, involves complicated chemical reactions associated with bond braking, radicals production and heat generation which are responsible for flames initiation. The conditions, such as pressure, temperature and mixture strength, make a strong influence on combustion. This paper reports an investigation of combustion characteristics of premixed propane/air flames and the effects of initial conditions on heat production rates, emissions (combustion products) and final equilibrium pressure and temperature values. Different mixtures concentrations were used in this study, including lean, stoichiometric and rich (f = 0.8, 1.0, 1.2), subject to different pressures and temperatures ranging from 5 - 40 bars and 350 - 600 K, respectively. Theelevated pressures and temperatures values were deliberately selected in this study to have more data available in the literature to fill in the gap in research and also to cover conditions that are similar to those in engines, in an attempt to have a better understanding on how to control emissions from these engines which is a major concern nowadays. Results show that rich mixture of propane fuel produces the highest rate for carbon monoxide (CO) with slight increase as pressure and temperature increase, where the stoichiometric mixture produces the highest rate of carbon dioxide (CO2). It was noted that this type of emission decreases with the increase of pressure and temperature. On the other hand, nitric acid (NO) was found to be the highest for the lean mixture with sharp increase as pressure and temperature increase. Finally, the combustion heat (Q) is extracted from each mixture which plotted against pressure and it was also found that rich mixture of this fuel produces the highest and increases sharply with increased pressures and temperatures.