A CFD study of propane/air microflame stability

A two-dimensional elliptic computational fluid dynamics model of a microburner is solved to study the effects of microburner wall conductivity, external heat losses, burner dimensions, and operating conditions on combustion characteristics and the steady-state, self-sustained flame stability of propane/air mixtures. Large gradients are observed, despite the small scales of the microburners. It is found that the wall thermal conductivity is vital in determining the flame stability of the system, as the walls are responsible for the majority of the upstream heat transfer as well as the external heat losses. Furthermore, there exists a range of flow velocities that allow stabilized combustion in microburners. It is found that the microburner dimensions strongly affect thermal stability. Engineering maps denoting flame stability are constructed and design recommendations are made. Finally, comparisons with methane/air systems are made.