Laminar diffusion flame in microgravity: The results of the MiniTexus 6 sounding rocket experiment

A flat plate of poly(methyl methacrylate) (PMMA) exposed on one surface to a laminar oxidizer Aom (40% oxygen and 60% nitrogen) was ignited at the downstream edge, allowing for propagation of a diffusion flame opposing the flow. The flame front is Rat, so edge effects can be neglected and the flame can be considered two-dimensional. The experiment was conducted on board a sounding rocket (MiniTexus 6) that provided 180 seconds of microgravity (10(-5)g(0)). Two charge-coupled device (CCD) cameras provided a lateral and a top view of the flame, and an infrared camera with a narrowband filter centered at 4.28 mum served to estimate the temperature of the PMMA surface. A green-light sheet perpendicular to the fuel surface, and a third CDD camera (side view) with a narrowband filter centered on the light served to record illuminated silver-coated glass beads. The glass beads follow the Row allowing the determination of streamlines and the estimation of the distortion of the flow field introduced by the flame. The experimental results are presented in the context of other experimental results obtained in drop towers and parabolic Rights. Experiments were conducted for three different Row velocities, 150 mm/s, 100 mm/s, and 50 mm/s, corresponding to strong propagation, transitional regime. and extinction regime, respectively. The experimental results provide evidence on the role of flame radiation, in-depth conduction, and surface reradiation in the low-velocity extinction process. The illuminated particles show that the flame modifies the flow structure upstream of the flame beyond the leading edge region. The effect of die flame on the Row decreases with the oxidizer velocity.