ON THE EFFECT OF PRESSURE IN METHANE-AIR FLAMES.

A non-steady, one-dimensional flame propagation model was applied to study the effect of pressure on flame velocity and flame thickness, temperature profile and concentration profiles in flat methane-air flames. A methane-oxygen reaction mechanism was used in the flame model, which permitted a satisfactory prediction of the effect of gas composition and of the temperature of unreacted gas misture. The calculated values of flame velocities at low pressures, where the experimental velocities show relatively high deviations, indicate a practically linear relation between the velocity and the reciprocal of the tenth root of pressure. At increased pressures the tenth root changes to a square root. The relative importance of each elementary reaction step and the hypothesis of partial equilibration of some important reactions are examined.