Spark ignition and stability limits of spray kerosene flames under subatmospheric pressure conditions

Abstract

Flame stability limits and ignition delay time of the flameholder are experimentally studied in this work at the pressure of 0.03 – 0.06 MPa, Mach number of 0.1 – 0.3, and temperature of 320 K – 800 K. The results indicate that the reduction in equivalence ratios of lean ignition and blowout can be achieved by the increase in pressure or Mach number. Temperature rise will first increase and then decrease the lean ignition equivalence ratio. While increasing lean blowout equivalence ratio was observed with increasing temperature. The envelope of the stable combustion between the pressure and Mach number is measured, and the lowest temperature of successful ignition is 300 K, acquired at Mach 0.1 and 0.06 MPa. Besides, the correlation between the equivalence ratios of flame stability and inlet parameters, such as pressure, Mach number, temperature, is developed. The ignition process of the flameholder is imaged, and the ignition delay time decreases with increased pressure or temperature. The ignition delay time is shown first to decrease and then increase with the increase in Mach number.