抄録
Microgravity experiments were performed on droplet evaporation of palm methyl ester (PME). Light oil and n-hexadecane were also examined as a reference fuel. Droplet temperature histories were obtained in addition to droplet diameter histories. Droplet temperature was measured with a K-type thermocouple (diameter: 13 μm). A small droplet (initial diameter: 0.30-0.40 mm) was employed for microgravity experiments in order to make effective use of short term microgravity. The droplet suspension system was improved to minimize the thermal effects of the suspension system on small droplet evaporation. Microgravity experiments at 773 K in the ambient temperature and from 0.1 to 2.0 MPa in the ambient pressure were performed with the CIT drop tower (microgravity duration: 1.1 s). It was found that the temporal variations of an evaporating droplet at normal and microgravity were almost identical when the time axis was normalized by the evaporation lifetime. The effect of natural convection on the droplet temperature at the end of evaporation was negligible.
