This module was developed by ATA Engineering as an add-on to the Loci/CHEM computational fluid dynamics (CFD) solver. The module implements the thickened flame model as a combustion model. The module artificially thickens the flame so that it can be resolved on a coarser grid. The flame thickening occurs by modifying the diffusion and reaction source terms in the species transport equations. Thickening the flame reduces its sensitivity to turbulent fluctuations. These combustion-turbulence interactions are modeled with an efficiency function that further modifies the diffusion and reaction source terms in the species transport equations.
This module depends on both Loci and CHEM being installed. Loci is an open source framework developed at Mississippi State University (MSU) by Dr. Ed Luke. The framework provides a rule-based programming model and can take advantage of massively parallel high performance computing systems. CHEM is a full featured open source CFD code with finite-rate chemistry built on the Loci framework. CHEM is export controlled under the International Traffic In Arms Regulations (ITAR). Both Loci and CHEM can be obtained from the SimSys Software Forum hosted by MSU.
First Loci and CHEM should be installed. The LOCI_BASE environment variable should be set to point to the Loci installation directory. The CHEM_BASE environment variable should be set to point to the CHEM installation directory. The installation process follows the standard make, make install procedure.
make
make installFirst the module must be loaded at the top of the vars file. The user can then specify the relevant thicked flame parameters within the thickenedFlame options list. The chemistry jacobian should be set through the tf_chemistry_jacobian variable, and the chemistry_jacobian variable should be set to none.
loadModule: thickenedFlame
thickenedFlame:<Fmax=10, pvBurnedValue=2000 K, pvUnburnedValue=300 K,
laminarFlameSpeed=0.1 m/s, laminarFlameThickness=0.001 m>
smoothingSteps: 14
chemistry_jacobian: none
tf_chemistry_jacobian: analytic