Abstract
To elucidate characteristics of a droplet flame as an elementary process of turbulent spray combustion, droplet combustion experiments in varying forced convection at high pressure were performed in microgravity. 1-butanole was used as a fuel and the maximum pressure was 1.0MPa. High-speed back lit images of burning droplet were obtained and time history of the droplet diameter was measured using image processing. Results showed that maximum velocity in oscillating flow is predominant for the burning rate constant, meaning that the classical quasi-steady assumption is not valid. Mechanism of this droplet combustion characteristic was discussed based on the ratio of characteristic time scales of flow oscillation and gas diffusion.
