Effect of Co-Axial Flow Velocity on Soot Formation in a Laminar Jet Diffusion Flame under Microgravity

Abstract

To examine the effect of low co-axial flow on soot formation in a laminar jet diffusion flame, microgravity experiments have been conducted. The tested co-axial flow velocity range is 0-7.3cm/s, which is very difficult to provide on the ground because of suffering from the additional external flow induced by buoyancy force. The result showed that the soot formation characteristics were greatly affected by co-axial flow velocity at the low flow velocity range, that is, soot concentration increased with increase in the external flow velocity. According to the radial distributions, the effect of external flow velocity on the soot formation was prominent near the outer edge of visible flame. A comparison with numerical calculation suggested that the increase of soot concentration was caused by increased flame temperature in the area of low oxygen and fuel excess region.