A method was developed to include the effect of volume expansion in the description of the flame dynamics using G-equation. Line volume source segments are used to model the mechanical effect of the exothermic process of combustion with source strength assigned by the density difference between the burned and unburned region.
The newly developed model provides an encouraging agreement with the experiment of flame-vortex interaction compared with the conventional G-equation solution. With volume expansion included, the flow field is adjusted to accommodate the increased volume flow rate crossing the flame front and the result predicts the same behavior of measured velocity field qualitatively.
The simulation reproduces the physical processes that are experimentally observed, namely the deformation of flame front due to the induced velocity from thermal expansion on the flame, flame attachment to a moving vortex and elongation, flame rollup, and burn-through of layers, formation of neck region and pockets of reactants, and final smearing of cusps. Net result of increasing volume expansion does not change the initial rate of flame wrinkling but increases the residence time and consequently the maximum flame wrinkling.
The flame propagation in the varying flow field due to volume expansion provides a promising way to represent very wrinkled turbulent premixed flames in a numerically efficient manner.