Laminar gas-jet diffusion flames of a nonsooting, fast reacting fuel were investigated at atmospheric pressure in microgravity and at different pressures in normal gravity. These weakly luminous flames were visualized and quantified using the rainbow schlieren deflectometry. The results show that the overall features of the microgravity flame are replicated in normal gravity experiments at sub-atmospheric pressures. The flame width in microgravity correlated with that in normal gravity, when the normalized Froude number at the burner exit was used as a parameter. Normal gravity experiments at low pressures produced nonbuoyant flames that remained parallel to the burner tube regardless of the tube's orientation with respect to the gravitational vector.

Effects of buoyancy on steady hydrogen gas-jet diffusion flames

The structure and soot properties of nonbuoyant laminar diffusion flames are being studied experimentally and theoretically in order to better understand the soot and thermal radiation emissions from luminous flames. The measurements involve weakly-buoyant flames at low pressure in normal gravity (ng) and nonbuoyant flames at normal pressures in microgravity (micro g). The objectives of the present investigation are to study the differences of soot properties between nonbuoyant and buoyant diffusion flames, and to evaluate predictions based on the laminar flamelet approach.

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Jongsoo Jurng

Papers

Structure and Soot Properties of Non-Buoyant Laminar Round-Jet Diffusion Flames