A predictive model and experimental verification for droplet size distribution of diesel-methanol-water emulsion in sprays

The spraying characteristics of the diesel-methanol-water emulsion were researched at different injection pressures by combining the principle of maximum entropy with experiments. The influences of the injection pressure, dispersed phase content and emulsifier on the spray's droplet size distribution were analyzed. The spray's probability density function of the emulsion was deduced through the principle of maximum entropy. Furthermore, a volume integral distribution model and a cumulative volume distribution model were established, and compared with the experimental results. The research shows that the distribution trend of the theoretical model based on the maximum entropy is consistent with the experimental distribution. With the increase of the injection pressure, the spray's Sauter mean diameter and the content of large droplets are reduced, while the content of small droplets is increased, and the peak of the distribution shifts to the smaller droplet diameter. Smaller dispersed phase content and weaker lipophilicity emulsifier may lead to a better atomization effect. The droplet diameter ranges from 10 μm to 60 μm, and the peak value is 30 μm. And near the peak, there is a maximum relative error between the theoretical and experimental diameters, and the distribution of theoretical values is more concentrated than the experimental values. With the increase of the injection pressure, the cumulative volume distribution curve becomes steeper, and the theoretical cumulative volume distribution reaches 100% faster than the experimental one.