Experimental determination of laminar burning velocity for butanol/iso-octane and ethanol/iso-octane blends for different initial pressures

The comparison of butanol/isooctane blends with an ethanol/isooctane blend was characterized with respect to laminar combustion, by using the spherical expanding flame methodology, in a constant volume vessel. This paper presents the results obtained for blends with alcohol concentrations of 0%, 25%, 50%, 75% and 100% (in volume) and an equivalence ratio ranging from 0.7 to 1.4, at different initial pressures (0.1, 0.3, 0.5 and 1.0 MPa) and an initial temperature of 423 K. The addition of alcohol to isooctane increases the laminar burning velocity, but increasing the initial pressure limits this increase. From burned gas Markstein length estimates, the flame of ethanol/isooctane and air mixture seems to be less sensitive to the total stretch rate and thermo-diffusive instabilities. From experimental data, a correlation with laminar burning velocity is suggested as a function of initial pressure, equivalence ratio and alcohol concentration.