Effects of wall confinement and temperature on laminar-flame propagation

A premixed laminar flame, freely propagating between parallel plates, was modelled two-dimensionally in terms of the conservation equations for energy and mass species. The flame system was taken to represent the global combustion of a kerosene-air mixture, with chemical kinetics of Arrhenius temperature-dependence and an over-all reaction order of 1·5. The modelling equations were solved numerically to yield the flame speed and two-dimensional flame structure at a certain distance separating the parallel plates. Solutions were obtained at various plate separations and wall temperatures in order to study the effect of wall confinement and temperature on laminar-flame propagation. The results showed that the wall started to affect the flame speed and maximum flame temperature slightly when the plate separation assumed values less than about 1 cm, while the heat-release rate exhibited an approximately linear decrease with the decrease in plate separation throughout the range studied. On the other hand, whereas the axial-flame structure showed only a slight variation with the distance separating the parallel plates, the transverse structure was much affected by the wall confinement and temperature where interesting results were obtained regarding the interaction between the flame and its containing walls.