ID 300

Evaporation of single droplets of multicomponent liquid fuel blends at elevated temperatures

 

Abstract:

The atomization and evaporation of fuels plays an indispensable role in the combustion process of di-rect injection engines. There is considerable interest in understanding the physics of the evaporation pro-cess of multi-component fuels, particularly at elevated temperature and pressure conditions representa-tive of internal combustion (IC) engines. In this work, the evaporation process of multi-component fuels is investigated by considering different mixture ratios of iso-octane and n-heptane at atmospheric pressure but elevated temperature conditions. Single droplet trains of different fuel blends are generated in a con-stant volume chamber whose temperature and pressure can be controlled as desired. The evaporation pro-cess of the droplets is visualized using a camera, which allows the change in droplet size to be measured as a function of time. The evaporation of single droplets of pure fuels is also calculated using a numerical model. The evaporation behavior is studied as a function of different ambient temperatures and fuel mix-tures. Good agreement is observed between the model predictions and experimental measurements for the pure fuels. The evaporation rate of n-heptane is observed to be higher than that of iso-octane as expected. Increase in ambient temperature is seen to increase the evaporation rate of fuel droplets. Increasing the concentration of n-heptane in the fuel mixture is seen to initially increase the evaporation rate. However, the highest evaporation rate is observed for an intermediate fuel blend and not for the case of pure n-heptane.