Characterization of Mixing and Flow Properties From Numerical Simulation of Cold Flow in Non-Premixed Combustor

In this work, large eddy simulation is applied to simulate cold flow in a combustor of non-premixed type. Air is introduced axially from the bottom of a cylindrical combustor whereas fuel is introduced directly in the combustion chamber. Two different geometries of fuel injection are taken which have been experimentally studied at Jadavpur University, India. Fuel is injected using two alternative orientations of the holes. In one orientation (referred to in this article as the vertical configuration), the fuel comes in vertically in parallel and counter-flow with the air stream. In the other orientation (referred to as the horizontal configuration), the fuel is injected horizontally at cross flow with the air stream. Two different kinds of dynamics have been achieved with two orientations in the experimental study [1]. In the present study, effort has been given to explore the flow behavior and mixing characteristics by simulating the combustion chamber with fuel injection similar to the experimental one. It is found that mixture fraction is more homogeneous due to the vortices formed downstream of the fuel inlet section for the horizontal configuration and also its value mostly remains in the flammability limit. As the parallel flow of fuel jet in the wake region hampers the vortex formation, convective mixing is very poor with vertical fuel injection.