Numerical simulation of combustion mechanism of fuel droplets under microgravity conditions- 2nd. report: the effect of fuel droplet evaporation-

摘要

The combustion mechanism of fuel droplets under microgravity was studied by numerical simulation. The effect of the extent of fuel droplet evaporation on the flame front speed was investigated by varying the ambient temperature and initial fuel temperature. A microgravity environment was used to prevent natural convection. Modeling was performed using the KIVA- III software package. Result showed that the flame front speed increased as the ambient temperature increased. Because the evaporation of fuel droplets was promoted by higher ambient temperatures. The flame front speed with the initial fuel temperature equal to the ambient temperature was larger than when the initial fuel temperature was lower than the ambient temperature. With a Sauter mean diameter of 7.5 μm, some fuel vapor remained in the burnt region. This was the group combustion mechanism caused by insufficient of oxygen. The effect of fuel droplet size on flame front speed was also investigated. No significant difference was found for Sauter mean diameters of 1.9, 4.7 and 7.5 μm.