  The mixing process of multiple jets of liquefied petroleum gas and air in a
diffusion flame is numerically analysed. The case study considers a four-port
array burner where the fuel is injected by four peripheral nozzles and mixed
with the surrounding air. Simulations are conducted with the Reynolds-Averaged
Navier-Stokes technique, and the turbulence effect is modelled with the
realizable k-e model. In addition, the eddy dissipation model is implemented to
calculate the effect of the turbulent chemical reaction rate. Results show that
the essential mixture mechanism occurs within a flame cone derived from the
fuel jets interaction. However, the mixing process is driven by jets drag
allowing an air/fuel smooth mixture to reach the flammability limits at two
zones: one at a lower location or close to the burner surface and a second
before the flame front development. The entire mixing mechanism culminates with
the development of the flame necking cone. Any air concentration that falls
into the cone radius will be entrained, contributing to the overall flame
structure. Since the cone radius reach is limited only by radial distance of
the jet array and the nozzles distance, the flame heights, consequently, depend
solely on fuel mass flow.
