The interactions between flame and vortex in a 2-D Trapped Vortex Combustor
are investigated by simulating the Reynolds Averaged Navier Stokes (RANS)
equations, for the following five cases namely (i) non-reacting (base) case,
(ii) post-vortex ignition without premixing, (iii) post-vortex ignition with
premixing, (iv) pre-vortex ignition without premixing and (v) pre-vortex
ignition with premixing. For the post-vortex ignition without premixing
case, the reactants are mixed well in the cavity resulting in a stable ?C?
shaped flame along the vortex edge. Further, there is insignificant change
in the vorticity due to chemical reactions. In contrast, for the pre-vortex
ignition case (no premixing); the flame gets stabilized at the interface of
two counter rotating vortices resulting in reduced reaction rates. There is
a noticeable change in the location and size of the primary vortex as
compared to case (ii). When the mainstream air is premixed with fuel, there
is a further reduction in the reaction rates and thus structure of cavity
flame gets altered significantly for case (v). Pilot flame established for
cases (ii) and (iii) are well shielded from main flow and hence the flame
structure and reaction rates do not change appreciably. Hence, it is
expected that cases (ii) and (iii) can perform well over a wide range of
operating conditions.
Numerical Study of NOx Generation in a Trapped Vortex Combustor Fuelled by Kerosene Blended with Ethanol
