Reports

MFIX-Exa provides several options for reporting data from the solver.

Particle size distribution

The particle size distribution (PSD) can be reported for different regions in the model. This feature requires a region already defined in the regions inputs, and only volume regions are valid for PSD reports. Each report must be associated with a single region; combining multiple regions in one report is not supported.

The following inputs are defined using the prefix output.reports:

Description

Type

Default

diameter

Names of the PSD reports

Strings

None

The following inputs are defined using the prefix output.reports.diameter.[report_name]:

Description

Type

Default

region

Region to compute the size distribution

String

None

int

Number of time steps between report outputs. Cannot be used with per_approx.

Int

None

per_approx

Simulation time (in seconds) between report outputs. Cannot be used with int.

Real

None

bins

Number of bins in PSD discretization

Int

None

min

Minimum particle size included in discretized PSD

Real

None

max

Maximum particle size included in discretized PSD

Real

None

A sample inputs snippet for outputting the particle size distribution is given below. Two regions are created that span the left and right sides of the domain, and used to create two reports. The left-side report is a PSD consisting of 32 bins between 30-3000 microns that is output every 50 time steps. The right-side report is a PSD consisting of 64 bins between 30-3000 microns that is output every 0.5 seconds of modeled time.

Listing 9 Snippet of inputs for particle size distribution reports.
# Define two regions for collecting report data
# -------------------------------------------------------------
regions = ... left right

regions.left.shape = box
regions.left.box.lo  = 0.00  0.00  0.00
regions.left.box.hi  = 0.05  0.10  0.10

regions.right.shape = box
regions.right.box.lo  = 0.05  0.00  0.00
regions.right.box.hi  = 0.10  0.10  0.10

# Define two particle size distribution reports
# -------------------------------------------------------------
output.reports.diameter = left-side  right-side

output.reports.diameter.left-side.region  = left

output.reports.diameter.left-side.int  =    50
output.reports.diameter.left-side.bins =    32
output.reports.diameter.left-side.min  =    30.0e-6
output.reports.diameter.left-side.max  =  3000.0e-6

output.reports.diameter.right-side.region  = right

output.reports.diameter.right-side.per_approx =  0.5
output.reports.diameter.right-side.bins =       64
output.reports.diameter.right-side.min  =       30.0e-6
output.reports.diameter.right-side.max  =     3000.0e-6

EB surface drag

Compute the surface drag on a region of the embedded boundary. Each report must be associated with a single region; combining multiple regions in one report is not supported.

The following inputs are defined using the prefix output.reports.eb_drag:

Description

Type

Default

regions

Names of the regions to report the surface drag.

Strings

None

The following inputs are defined using the prefix output.reports.eb_drag.[region_name]:

Description

Type

Default

int

Number of time steps between report outputs. Cannot be used with per_approx.

Int

None

per_approx

Simulation time (in seconds) between report outputs. Cannot be used with int.

Real

None

Listing 10 Snippet of inputs for EB drag reports.
# Define region for collecting report data
# -------------------------------------------------------------
regions = ... eb_cyl

regions.eb_cyl.shape = cylinder
regions.eb_cyl.cylinder.radius = 0.075
regions.eb_cyl.cylinder.start = 0.2  0.0  -0.205
regions.eb_cyl.cylinder.end   = 0.2  0.0   0.205

# Define the EB drag report
# -------------------------------------------------------------
output.reports.eb_drag.regions = eb_cyl

output.reports.eb_drag.eb_cyl.int = 500

Mass balance

Report the mass balance in the domain for chemically reacting flows. The report is written to standard out at the specified interval, summarizing the current and previous mass values, the computed production, mass in, mass out, net accumulation and flux.

The following inputs are defined using the prefix output.reports.mass_balance:

Description

Type

Default

int

Number of time steps between report outputs. Cannot be used with per_approx.

Int

None

per_approx

Simulation time (in seconds) between report outputs. Cannot be used with int.

Real

None

Below is an example mass balance report.

Listing 11 Example mass balance report.
**************************************************************************************************************
  Species mass balance for interval:      5.000341  to     5.000350

  Species     mass(t+dt)      mass(t)     production      mass(in)     mass(out)      net accu       flux
  CH4         2.1712e-05    2.1665e-05   -1.0798e-09    1.8712e-09    7.2078e-12    4.7639e-08    1.8640e-09
  H2          6.4846e-08    6.4474e-08   -1.7595e-11    2.9835e-11    1.1274e-14    3.8898e-10    2.9824e-11
  CO          2.1639e-06    2.1548e-06   -3.3894e-10    5.7213e-10    1.0023e-14    9.3595e-09    5.7212e-10
  H2O         5.6031e-03    5.5963e-03    2.5824e-09    1.2061e-08    2.0207e-08    6.8486e-06   -8.1456e-09
  CO2         8.8658e-03    8.8514e-03    3.4948e-09    1.5164e-08    1.9451e-08    1.4334e-05   -4.2871e-09
  O2          7.2834e-04    7.2826e-04   -1.9539e-08    2.9507e-08    6.2867e-09    1.0697e-07    2.3220e-08
  N2          1.0325e-02    1.0319e-02    0.0000e+00    9.7177e-08    1.0018e-07    6.0370e-06   -2.9990e-09
  Fe2O3       1.1709e+01    1.1709e+01    1.4870e-07    0.0000e+00    0.0000e+00   -1.1463e-15    0.0000e+00
  FeO         1.0425e+01    1.0425e+01   -1.3380e-07    0.0000e+00    0.0000e+00    4.3730e-16    0.0000e+00
  inert       6.9886e+01    6.9886e+01    0.0000e+00    0.0000e+00    0.0000e+00    0.0000e+00    0.0000e+00
--------------------------------------------------------------------------------------------------------------
  Total       9.2046e+01    9.2046e+01    5.3998e-21    1.5638e-07    1.4613e-07    2.7384e-05    1.0254e-08

  total number of particles =    5,234,191,099
  |(total acc) - (net flux)| =      2.7373e-05
**************************************************************************************************************