freefoam-Xi — Solver for compressible premixed/partially-premixed combustion with turbulence modelling.
Combusting RANS code using the b-Xi two-equation model. Xi may be obtained by either the solution of the Xi transport equation or from an algebraic exression. Both approaches are based on Gulder’s flame speed correlation which has been shown to be appropriate by comparison with the results from the spectral model.
Strain effects are encorporated directly into the Xi equation but not in the algebraic approximation. Further work need to be done on this issue, particularly regarding the enhanced removal rate caused by flame compression. Analysis using results of the spectral model will be required.
For cases involving very lean Propane flames or other flames which are very strain-sensitive, a transport equation for the laminar flame speed is present. This equation is derived using heuristic arguments involving the strain time scale and the strain-rate at extinction. the transport velocity is the same as that for the Xi equation.