THE EFFECT OF INLET CONDITION ON THE COMBUSTION IN A POROUS-FREE FLAME BURNER

Premixed combustion in "porous" and novel "porous-free flame" burners are studied using numerical simulations in an axisymmetric combustion chamber. The porous medium is perforated along the axis to create a combination of a free flame and porous burner. The governing equations are solved using the finite volume numerical method. A reduced chemical mechanism and a realizable k-epsilon turbulence model are used for simulation. In order to validate the numerical results, both burners have been constructed and tested. The obtained numerical results showed a good agreement with the experimental data. The numerical results showed that the flame of the porous-free flame burner has a greater stability limit than that of the porous burner. The effect of the inlet condition is studied so that with increasing equivalence ratio, the lower stability limit always increases, but the upper stability limit first increases and then decreases. The maximum upper limit of stability is obtained in the equivalence ratio of 0.9. The effect of change in temperature of the inlet mixture (300, 450, and 600 K) on flame location and flame stability limit is investigated. It is observed that the flame stability limit increases with increasing inlet mixture temperature.