Abstract
In the present study, the ignition characteristics of liquid fuel were experimentally investigated. To quantify its ignitability as ignition characteristics, the minimum ignition energy (MIE) of liquid fuel was defined and measured under at the elevated oxygen concentrations and reduced atmospheric pressures which that are the most probable conditions likely to be encountered during operation of the space launch vehicle's operating process. The experimental results demonstrate that the measured MIE decreased with the increasing the oxygen concentration at given atmospheric pressures. When the atmospheric pressure was reduced from 1 atm to 0.2 atm at a fixed oxygen concentration, the measured MIE was found to vary with $P^{-2}$ but the lowest MIE was observed at 0.8 atm.