Effects of gravitational acceleration on high pressure combustion of methanol droplets

A Franco-Japanese cooperative research program on microgravity combustion h as been initiated. One of the studies is devoted to the experimental invest igation of high pressure combustion of methanol droplets, under normal and reduced gravity conditions, which are obtained in a drop tower and during t he parabolic flight of an airplane. A methanol droplet is suspended at the center of a high-pressure combustion chamber, and is ignited with an electr ically heated kanthal wire. A high-speed video camera is used to obtain the time histories of the squared droplet diameter, which are used to determin e the droplet burning rate. The results show that the d-square law is valid for all the conditions of the present experiments. The droplet burning rat e increases with ambient pressure and does not show a maximum around the cr itical pressure of methanol. Experiments also show that the droplet burning rate decreases with the reduction of gravitational acceleration.