Temperature-Field Analysis of Flame Spread over Droplet-Cloud Elements with Interactive Droplets in Microgravity aboard Kibo on ISS

Abstract

Liquid-fuel combustion experiments titled “Elucidation of Flame Spread and Group Combustion Excitation Mechanism of Randomly Distributed Droplet Clouds (Group Combustion)” were conducted in 2017 as the first of the combustion experiments in the Japanese Experimental Module “Kibo” aboard the International Space Station (ISS). This paper reports temperature-field analysis by the TFP method based on visible light emissions for the flame spread of droplet-cloud elements composed of four droplets with two or three interactive droplets, which was conducted as part of the “Group Combustion” experiments. The results show that the position of the interactive droplets affects the flame spread around the droplets, and the flame-spread limit is extended by the interactive effect. If a burning droplet pre-heats a droplet existing outside the flame-spread limit, the pre-vaporization also extends the flame-spread limit around two interactive droplets.