Computational Studies of Turbulent Flow in an Isothermal Suddenly Enlarged Combustion Chamber

The present work is concerned with computational studies of turbulent flow under isothermal condition in a suddenly enlarged combustion chamber using time averaged Navier-Stokes equations with an eddy-viscosity turbulence closure model. Results were compared well with that of experimental data available in open literature. The effect of inlet turbulence intensity is found to be the dominant parameter determining the flow field. However this effect is found to be decreasing with the increase in the expansion ratio. The increase of turbulence level decreases the reattachment length due to the energy supply to the separating shear layer, which is a major factor determining the reattachment length. It has been found out that for same expansion ratio, the reattachment length attains a minimum value for low turbulence Reynolds number, increases with increase in Reynolds number, and attains a maximum limit. Both the turbulent kinetic energy and the turbulent dissipation rate are found to be maximum in the shear layer and also keep increasing with the increase in turbulence intensity.