### 3.2.16. CFX Radiation File

When using the Monte Carlo or Discrete Transfer radiation models, output information for radiation is written to a results data file named `results.<groupname>_<accumulated timestep>.dat` (steady state cases) or `results.<groupname>_<accumulated timestep>_<accumulated iteration number>.dat` (transient cases), where `<groupname>`, `<accumulated timestep>`, and `<accumulated iteration number>` are substituted with appropriate names/values.

A sample `results.<groupname>_<accumulated timestep>.dat` file is shown below:

    Zone         Volume    Temperature Refr. B=1  Emiss Co.  Scat Co.   ...
    Room$1       1.309E-02  2.951E+02  1.000E+00  1.000E-02  0.000E+00  ...
    Room$2       1.104E-02  2.951E+02  1.000E+00  1.000E-02  0.000E+00  ...
    .
    .
    .
    Room$1551    2.172E-03  2.951E+02  1.000E+00  1.000E-02  0.000E+00  ...
    Room$1552    5.090E-04  2.951E+02  1.000E+00  1.000E-02  0.000E+00  ...

    Total heating and cooling   4.130E+02   3.873E+02

    Total path length    1.834E+00

    Surface data

    Zone         Surface               Area     Temperature Rough   Emiss    ...

    Room$1       Room Default$1        6.774E-02  2.991E+02 1.00  1.000E+00  ...
    Room$1       VentOut$2             3.232E-02  2.951E+02 1.00  1.000E+00  ...
    Room$2       VentOut$12            2.532E-02  2.951E+02 1.00  1.000E+00  ...
    .
    .
    .
    Room$1551    Room Default$10633    2.166E-02  2.991E+02 1.00  1.000E+00 ...
    Room$1552    Room Default$10634    1.376E-02  2.991E+02 1.00  1.000E+00 ...

    Total surface heating and cooling     2.211E+04   2.179E+04

    Total non-thermal emission   3.464E+02

    Net total absorbed power     3.624E+00    1.609E-06%

    Total surface current and absorbed flux:-     9.818E-01   1.834E-02

    PROCESS   1
    ***********

    Number of histories      29423

     IWORK =     264568
     CPU time used     6.906

#### 3.2.16.1. CFX Radiation File Contents

A CFX Radiation file contains the volume information, surface information, and some miscellaneous quantities such as the net total heating; parameters that measure the work needed and the CPU time used. Finally, if radiometers have been included, the results for each radiometer will be printed out. Note that the CPU time does not include the time required to compute the radiometer value.

#### 3.2.16.2. Volume Information

The volume information is given in a table with the following columns:

- `Zone` is the radiation element’s internal name

- `Volume` is the volume of the radiation element

- `Temperature` is the temperature of the element

- `Refr. B=1` is the refractive index of the element

- `Emiss Co.` is the emission coefficient (Units: per length)

- `Scat Co.` is the scattering opacity coefficient (Units: per length)

- `Path len.` is the average length when crossing a radiation element

- `Heating` is average volumetric absorbed radiation

- `Emission` is the volumetric emitted radiation

- `(H-E)*VOL` is the amount of radiative energy that shows up as a square term in the energy equation

- `Error %` is the standard deviation of the path length.

For non-gray models the emission and scattering coefficients are the spectrum integrated coefficients. In a gray model the absorption coefficient equals the emission coefficient, in a non-gray model it can be obtained from the intensity and the heating.

The next five columns contain the results. The seventh is the total path length of photons in the zone (Monte Carlo) or the mean radiation intensity (discrete transfer). The eighth is the heating per unit volume, the ninth the cooling per unit volume, and the tenth the net total radiative heating rate for the zone. The last column gives the statistical percentage error for Monte Carlo or the number of samples (rays traced through the zone) used for the heating quadrature in the discrete transfer case.

Finally comes the total heating and cooling rates for the entire volume and, for Monte Carlo, the total mean path length of photons in the geometry. Non-gray models will also have the band by band cooling.

#### 3.2.16.3. Surface Information

In this output the first column is the zone name and the second the surface name. The third is the surface temperature, the fourth the surface roughness and the fifth is the surface emissivity, spectrum integrated in the case of a non-gray model. Grey surfaces have an albedo equal to one minus the emissivity, in the non-gray case the integrated albedo can be obtained from the surface heating and the incident flux.

The next five columns contain the results. The sixth is the surface current (Monte Carlo) or average incident radiation flux (discrete transfer). The seventh is the heating per unit area, the eighth the cooling per unit area and the ninth the net total radiative heating. The last column is the statistical error (Monte Carlo) or the number of surface nodes used for sampling (discrete transfer).

Finally comes the total heating and cooling rates for all the surfaces in the geometry. Non-gray models will also show the band by band cooling.

After the above information, the overall net heating for the model is printed. This is a measure of how good the calculation was because this figure should be zero. For a Monte Carlo calculation the total surface current and absorbed photon flux is printed, these figures should sum to unity and can therefore be used as another measure of the accuracy of the calculation. Next the number of histories computed (Monte Carlo) or the number of angular ordinates (Discrete transfer) is printed. The last numbers are the work estimator and the CPU time. The work estimator is defined in terms of units of work where a unit of work is the computational effort to trace a photon (ray) to the next event (surface) and process that event (update the recursion relation) for Monte Carlo (Discrete transfer). If radiometers have been calculated, the angular calibration table that is used will be printed; then for each radiometer location, the following will be written: location, direction, temperature, flux.

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