Characteristics of diffusion flames with accelerated motion

Abstract

The aim of this work is to present an experiment to study the characteristics of a laminar diffusion flame under acceleration. A Bunsen burner (nozzle diameter 8 mm), using liquefied petroleum gas as its fuel, was ignited under acceleration. The temperature field and the diffusion flame angle of inclination were visualised with the assistance of the visual display technology incorporated in MATLAB™. Results show that the 2-D temperature field under different accelerations matched the variation in average temperatures, they both experience three variations at different time and velocity stages. The greater acceleration has a faster change in average temperature with time, due to the accumulation of combustion heat, the smaller acceleration has a higher average temperature at the same speed. No matter what acceleration was used, in time, the flame angle of inclination increased, but the growth rate decreased until an angle of 90°. This could be explained by analysis of the force distribution within the flame. It is also found that, initially, the growth rate of angle with velocity under the greater acceleration was always smaller than that at lower accelerations, and it was also different in flames with uniform velocity fire conditions.

Association of flame-oscillation frequency under cross wind diffusion

“…The flame image sequence in fig. 2 shows that as the wind speed increases, the angle of the flame that deviates from the vertical direction increased [16], and the visible area of the flame plume decreased [17].…”