Numerical and experimental study on the flame flow field near the fuel nozzle tip

Abstract

The generation of a recirculation zone in jet flow has recently been demonstrated to influence flame stability and soot formation. In this study, we conducted both experiments and numerical simulations to elucidate the mechanisms underlying vortex formation in laminar coflow diffusion flames. Numerical models were developed by incorporating various parameters, including fuel density, jet velocity, fuel temperature, and ambient air temperature. The flow patterns near the nozzle indicated how these parameters affect the development of the recirculation zone. Simulation results were validated against experimental data. Among the studied parameters, fuel density, jet velocity, and nozzle diameter emerged as the primary factors influencing recirculation flow, whereas fuel and ambient air temperatures exerted secondary effects. Detailed analysis of each parameter unveiled critical conditions at which the recirculation zone forms.