The present study aims to establish a new experimental methodology (Fine Wire Sustaining method, FWS) and to obtain the fundamental data of spray combustion, the combustion of the liquid fuel droplets cloud. To simulate the fuel droplet cloud, each droplet was suspended at points of intersection of fibers. The geometrically controlled droplets arrayed in two or three dimensions imitated the liquid fuel droplet cloud. The experiments were performed to investigate the flame shape and the ignition delay of the droplet cloud in high temperature. The influences of the surrounding droplets on the flame shape and on the ignition delay of the center droplet were investigated. The droplet distance was the experimental parameters. As a result of the experiments, the combustion characteristic of the droplet cloud could be investigated by using the new experimental methodology. The flame shape of the fuel droplet cloud could be classified by using the group combustion number G. The ignition delay of the center droplets arrayed in three dimensions decreased with the droplet distance to the extent that the flames are isolated.
The influence of ultrasonic vibration on the degree of supercooling was investigated for disodium hydrogenphosphate dodecahydrate, which is used in longterm, supercooled thermal energy storage (Super-TES). Super-TES stores thermal energy at temperatures lower than the melting point of the phase-change material, which reduces heat loss from the storage system. The supercooled hydrate in a test tube was experimentally vibrated at four different frequencies, 24kHz, 43kHz, 90kHz, and 996kHz, and different sound power. Experimental results show that the degree of supercooling is independent of the ultrasonic vibration. No bubbles were observed in the hydrate though tiny bubbles by cavitation were observed in the water outside of the test tube. When a stainless steel rod existed in the supercooled hydrate, however, the rod was vibrated by the ultrasonic vibration and rubbed the surface of the test tube, which promoted nucleation in the hydrate.