Combustion Oscillation in Oil Mist Firing

Abstract

This paper deals with the unstable combustion of liquid fuel in a combustor. Owing to the increase of air-fuel ratio in the range larger than stoichiometric one, combustion becomes unstable, the noise increases and also the pressure and the temperature in the combustor oscillate at a frequency of 20 to 50 cps. Moreover, blow-off phenomenon results from this unstable combustion. The results obtained are as follows : (1) The frequency of combustion oscillation changes with air-fuel ratio, fuel flow rate and mean drop size of fuel. (2) The amplitudes of pressure and temperature change become larger with the increase of air-fuel ratio and fuel flow rate. (3) The flow rates of fuel and atomizing air oscillate in the case of combustion oscillation. (4) The mechanism of combustion oscillation is made clear by high speed photography.