Numerical investigation of turbulent combustion regimes on localized forced ignition using stratified combustible mixture

Abstract

Localized forced ignition of turbulent stratified mixtures has been numerically analyzed based on three- dimensional Direct Numerical Simulations (DNS) for different values of Karlovitz number (Ka) corresponding to different turbulent combustion regimes. The initial values of turbulent fluctuations and the integral length scale of turbulence have been modified to bring about the change in Ka. The localized forced ignition is accounted by a source term in the energy transport equation which deposits energy over a time interval. It has been found that combustion takes place predominantly under a premixed mode of combustion following successful ignition. An increase in Ka has shown an increase in Minimum Ignition Energy (MIE) and has been shown to have adverse effects on the burned gas mass. Additionally, a stratified combustion mixture has been found to be a more favorable choice over homogeneous mixtures for a given turbulent ow condition for achieving a higher burning rate.