Paper 41: The Spontaneous Ignition and Ignition Delay of Liquid Fuel Droplets Impinging on a Hot Surface

The spontaneous ignition and ignition delays of liquid fuel droplets impinging on a hot surface are investigated. It is shown that the ignition delay–temperature curves follow closely the pattern of lifetime–temperature curves and that for the commercially important fuels, such as kerosine and diesel fuel, the ignition delays have a minimum value at some particular temperature. Zones of non-ignition are isolated and a hypothesis presented for their occurrence. It is further shown that within the temperature range investigated, the ignition delays of droplets impinging on a hot surface are much shorter than those of similar droplets undergoing spontaneous ignition when suspended in a stagnant atmosphere.