Advanced finite-volume numerics and source term assumptions for G-Equation modelling of propane/air flames
G-Equation models represent propagating flame fronts with an implicit two-dimensional surface representation (level-set). Level-set methods are fast, as transport source terms for the implicit surface can be solved with finite-volume operators on the finite-volume domain, without having to build the actual surface. However, they carry out several approximations and assumptions whose practical impact on the accuracy of combustion simulations is often not properly understood. In this study, we analyzed all source terms making up the FRESCO CFD code’s G-Equation solver for simulating propane/air flames. We employed three well-established constant-volume configurations: a one-dimensional, freely-propagating laminar flame; a disc-shaped, constant-volume swirl combustor; and torch-jet flame development through an orifice from a two-chamber device. We tested the explicit (sub-cycled) vs. implicit formulation for the standard transport operators (advection, diffusion, compressibility).