Statistical analysis of onset of microexplosion for an emulsion droplet

Abstract

A experimental study has been carried out on the burning behavior of an emulsion droplet suspended on a quartz fiber. Attention was paid mainly to the coccurrence of microexplosion, which may be caused by the bubble nucleation at temperatures below the superheat limit. The oil-in-water emulsion consisting of the base fuel and water was employed after degasification. The base fuels used were n-tetradecane and n-hevadecane. The water content varied from 0.1 to 0.3 by volume. The waiting time for the onset of microexplosion was measured for about 30 runs. The microexplosion is assumed to be a random process, and the onset probability of microexplosion was discussed from the statistical point of view. The Weibull distribution, which is derived mathematically from the weakest link destruction model, was adopted for this purpose. The results showed that the distribution function of the waiting time correlated with the Weibull distribution. The distribution function is classified the wearout type at the initial heating period and as the chance failure type at the constant-temperature period. Thus, the type of Weibull distribution of the waiting time is dependent on the variation of the droplet temperature with time. The onset rate of microexplosion increases exponentially as the superheating of water increases. The reliance of the onset rate on the superheating of water is independent of the base fuel.