Experimental study of the structure of laminar premixed flames of ethanol/methane/oxygen/argon

The structures of three laminar premixed stoichiometric flames at low pressure (6.7 kPa): a pure methane flame, a pure ethanol flame, and a methane flame doped by 30% of ethanol, have been investigated and compared. The results consist of mole fraction profiles of CH$_4$, C$_2$H$_5$OH, O$_2$, Ar, CO, CO$_2$, H$_2$O, H$_2$, C$_2$H$_6$, C$_2$H$_4$, C$_2$H$_2$, C$_3$H$_8$, C$_3$H$_6$, CH$_3$–C $\equiv$ CH (propyne), СН$_2$=С=СН$_2$ (allene), CH$_2$O, and CH$_3$HCO, measured as a function of the height above the burner by probe sampling followed by on-line gas chromatography analyses. Flame temperature profiles have been also obtained by using a PtRh thermocouple. The similarities and differences between the three flames have been analyzed. The results show that, in these three flames, the mole fraction of the intermediates with two carbon atoms is much larger than that of the species with three carbon atoms. In general, the mole fraction of all intermediate species in the pure ethanol flame is the largest, followed by the doped flame, and finally the pure methane flame.