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Large Eddy Simulations of Oxy-Coal and Gasification Flames

Oxy-coal flame simulation

Input file

The following input file was used to specify the simulation specifications:

Input files:

The following variables describe the particle characteristics:

  • length: particle diameter
  • ux, uy, uz: particle velocity components
  • pT: particle temperature
  • RCmass: raw coal mass
  • Charmass: char mass

These variables are solved for each quadrature node and the suffix "_qn" followed by the quadrature node number determines which quadrature node is associated with the variable. The suffix "_icv" indicates it is the internal coordinate value as opposed as the weighted value. For instance, weight_qn0 is the number density of small particles (40 microns), length_icv_qn0 is the diameter of the small particles (40 microns) whereas length_qn0 is the weighted length, which is equal to the product of weigh_qn0 and length_qn0_icv. Boundary conditions need to be specified in the BoundaryConditions section for each variable on each faces of the domain.

Coal properties are specified in the Coal_Properties section. It includes the initial coal elemental composition as well as the particle density and the initial raw coal and ash mass for each quadrature node (char mass is initially zero by default).

The combustion in the gas phase is modeled by a mixture fraction approach. The two transported mixture fractions are defined in the TransportEqns section with their associated source terms.

Properties of the gas phase are set by a pre-computed table, which is specified in the Properties section. The reaction table "zhang5.mix" can be found here and corresponds to 21% oxygen in the primary stream.

The DQMOM section includes several blocks:

  • LinearSolver: the user has to specify the optimal abscissas,
  • VelModel: the Dragforce model is generally used,
  • Models: a list of all the models used for the particle internal coordinates
  • Weights: this section initializes the number density for each abscissa,
  • Ic: initialization of each internal coordinates and specification of the models to be applied,
  • Moments: a list of the moments that will be used in the DQMOM method.