Spontaneous ignition of n-alkane droplets with varied volatility

Ignition delays of cool flame (tau1) and of hot flame (tau-t) are experimentally measured for single n-decane, n-dodecane, n-tetradecane and n-hexadecane droplets, which have corresponding volatility to prevailing commercial hydrocarbon films, in hot air. Droplet diameter is 0.7 mm. Ambient pressure is 0.3 and 1.0 MPa. Ambient temperature is 550 1000 K. Results show the similarity of the examined fuels in terms of reactivity of the low- and high-temperature reactions. Tau1 and tau-t are longer for fuels with less volatility, and tau2(= tau-t tau1) is similar for the examined fuels. Ignition limits for cool flame and for hot flame are also similar, while they are slightly lower for fuels with less volatility. (Author)