PDRFoam.C File Reference

Solver for compressible premixed/partially-premixed combustion with turbulence modelling. More...

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Detailed Description

Solver for compressible premixed/partially-premixed combustion with turbulence modelling.

Original source file PDRFoam.C

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 expression. 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 incorporated 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.

For large flames e.g. explosions additional modelling for the flame wrinkling due to surface instabilities may be applied.

PDR (porosity/distributed resistance) modelling is included to handle regions containing blockages which cannot be resolved by the mesh.

The fields used by this solver are:

betav: Volume porosity Lobs: Average diameter of obstacle in cell (m) Aw: Obstacle surface area per unit volume (1/m) CR: Drag tensor (1/m) CT: Turbulence generation parameter (1/m) Nv: Number of obstacles in cell per unit volume (m^-2) nsv: Tensor whose diagonal indicates the number to subtract from Nv to get the number of obstacles crossing the flow in each direction.

Definition in file PDRFoam.C.