Virtual Chemistry for Large Eddy Simulation: A Speedup Framework for Turbulent Combustion

Detailed chemical kinetics dominate Large Eddy Simulation wall-clock cost in turbulent combustion. This work presents a Virtual Chemistry framework for CxHy/air combustion replacing detailed mechanism by a compact set of virtual species. Unlike original mass-based formulation, each virtual species carries its own synthetic element composition and its molecular mass, so NASA7 polynomials are fitted directly and the CFD solver parses the virtual mechanism through the same Cantera interface as GRI3.0. NSGA-3 optimizes kinetic parameters against flamespeed and thermodynamic residuals, this approach yields a speedup factor of 108 to 360 in 1D flame evaluations depending on the detailed baseline, with laminar flame speed matched within a few percent, integrated into the in-house MFSim CFD code