Ignition of mixture gas with coal dust and lime dust (2D)

Update: February 2, 2018
OpenFOAM 4.x

Case directory

$FOAM_TUTORIALS/lagrangian/coalChemistryFoam/simplifiedSiwek

Summary

We calculate combustion of coal dust and lime dust. The dust is mixed by the force of the pressure difference and then ignited. The flow of the coal dust and lime dust is calculated using the particle function, but the particles here are not actual dust particles but Lagrangian particles (i.e. particles as calculation points).

The model geometry is shown in the figure below and the calculation is performed as two-dimensional. The region "top", "bottom", and "walls" are all static walls, and the region "symmetry" is a symmetry plane. And region "top" and "bottom" are adiabatic, and the region "walls" are fixed at 400 K. At time 0, the pressure in the narrow area extending from top is set to 5.0✕105 Pa, and the pressure in the lower chamber is set to 1.0✕105 Pa. The pressure difference drives the flow. At time 0.1 sec, the mixture gas is ignited at position "ignitionCells" and is calculated until time 0.5 sec.

Model geometry Model geometry

The initial positions of the Lagrangian particles of coal dust and lime dust are defined in the files "coalCloud1Positions" and "limestonePositions" in the directory "constant", respectively, and the properties of their motion are defined in the files "coalCloud1Properties" and "limestoneCloud1Properties" in the same directory.

The properties of combustion reactions and chemical species are defined in the file "foam.inp" and the file "foam.dat" in the directory "constant", which are referenced from the file "thermophysicalProperties". In addition, the file "fvOptions" in the same directory defines the ignition location, the file "chemistryProperties" defines the chemical reaction calculation settings, and the file "radiationProperties" defines the radiation settings.

The meshes are as follows, and the number of mesh is 2518.

Mesh Meshes

The calculation result is as follows.

After ignition, water (steam) is produced in the analysis area according to the following equation.

  • CH4 + O2 → CO2 + 2H2O
  • 2H2 + O2 → 2H2O
Water (H2O)
The motion of a Lagrangian particle (white: coal, red: lime)
Temperature at 0.05 sec (T) Temperature at 0.05 sec (T)
Temperature at 0.2 sec (T) Temperature at 0.2 sec (T)
Temperature at 0.5 sec (T) Temperature at 0.5 sec (T)
Flow velocity at 0.05 sec (U) Flow velocity at 0.05 sec (U)
Flow velocity at 0.2 sec (U) Flow velocity at 0.2 sec (U)
Flow velocity at 0.5 sec (U) Flow velocity at 0.5 sec (U)

Visualization

To visualize the Lagrangian particles, after loading the data, go to the time where the particle data exist (i.e. other than time 0), check only "coalCloud1" and "limestoneCloud1" in the Mesh Parts list of the pipeline browser, and click the Apply button.

Select display items Select display items

Commands

cp -r $FOAM_TUTORIALS/lagrangian/coalChemistryFoam/simplifiedSiwek simplifiedSiwek
cd simplifiedSiwek

blockMesh
topoSet

coalChemistryFoam

paraFoam

Calculation time

2 minutes 29.23 seconds *Single, Inter(R) Core(TM) i7-2600 CPU @ 3.40GHz 3.40GHz

Reference