Flame Spread of Fuel Droplet Array in a Fuel Vapor-Air Mixture

摘要

A new apparatus for microgravity experiments has been developed to study flame spread along a fuel droplet array in a fuel vapor-air mixture as a simple model of droplet combustion in a spray flame. The purpose of this research is to examine the effect of fuel vapor concentration of an ambient gas on the flame spread. Since fuel droplet of about one millimeter in diameter are employed for precise observation and easy handling, microgravity experiments are necessary to eliminate the effect of natural convection. Several fuel droplets were simultaneously generated in a straight line with very thin glass tubes and suspended at the crossing points of X-shaped suspenders. Fuel vapor-air mixture was filled in a combustion chamber, at the bottom of which there is a slit with a shutter. After the shutter was opened, the droplet array was inserted into the combustion chamber from the slit. The droplet at the one end was ignited to initiate flame spread. Performance tests of the developed experimental apparatus were conducted. Gas equivalence ratio around a droplet array can be controlled successfully. Droplets remained at the suspenders even in strong flow of burnt gas.