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22.16.2 Reporting of Trajectory Fates

When you perform trajectory calculations by displaying the trajectories (as described in Section  22.16.1), FLUENT will provide information about the trajectories as they are completed. By default, the number of trajectories with each possible fate (escaped, aborted, evaporated, etc.) is reported:

DPM Iteration ....
num. tracked = 7, escaped = 4, aborted = 0, trapped = 0, evaporated = 3, inco
Done.

You can also track particles through the domain without displaying the trajectories by clicking on the Track button at the bottom of the panel. This allows the listing of reports without also displaying the tracks.



Trajectory Fates


The possible fates for a particle trajectory are as follows:



Summary Reports


You can request additional detail about the trajectory fates as the particles exit the domain, including the mass flow rates through each boundary zone, mass flow rate of evaporated droplets, and composition of the particles.

1.   Follow steps 1 and 2 in Section  22.16.1 for displaying trajectories.

2.   Select Summary as the Report Type and click Display or Track.

A detailed report similar to the following example will appear in the console window. (You may also choose to write this report to a file by selecting File as the Report to option, clicking on the Write... button (which was originally the Display button), and specifying a file name for the summary report file in the resulting Select File dialog box.)

DPM Iteration ....

num. tracked = 10, escaped = 8, aborted = 0, trapped = 0, evaporated = 0, inc

 Fate                 Number           Elapsed Time (s)
                                     Min        Max        Avg    Std Dev
 ----                 ------  ---------- ---------- ---------- ---------- ---
 Incomplete                2   1.485e+01  2.410e+01  1.947e+01  4.623e+00
 Escaped - Zone 7          8   4.940e+00  2.196e+01  1.226e+01  4.871e+00

                  (*)- Mass Transfer Summary -(*)

 Fate                      Mass Flow (kg/s)
                         Initial      Final     Change
 ----                 ---------- ---------- ----------
 Incomplete            1.388e-03  1.943e-04 -1.194e-03
 Escaped - Zone 7      1.502e-03  2.481e-04 -1.254e-03

                  (*)- Energy Transfer Summary -(*)

 Fate                      Heat Content (W)
                         Initial      Final     Change
 ----                 ---------- ---------- ----------
 Incomplete            4.051e+02  3.088e+02 -9.630e+01
 Escaped - Zone 7      4.383e+02  3.914e+02 -4.696e+01

                  (*)- Combusting Particles -(*)

 Fate                   Volatile Content (kg/s)        Char Content (kg/s)
                         Initial      Final   %Conv     Initial      Final
 ----                 ---------- ---------- -------  ---------- ---------- --
 Incomplete            6.247e-04  0.000e+00  100.00   5.691e-04  0.000e+00  1
 Escaped - Zone 7      6.758e-04  0.000e+00  100.00   6.158e-04  3.782e-05

Done.

The report groups together particles with each possible fate, and reports the number of particles, the time elapsed during trajectories, and the mass and energy transfer. This information can be very useful for obtaining information such as where particles are escaping from the domain, where particles are colliding with surfaces, and the extent of heat and mass transfer to/from the particles within the domain. Additional information is reported for combusting particles.

Elapsed Time

The number of particles with each fate is listed under the Number heading. (Particles that escape through different zones or are trapped at different zones are considered to have different fates, and are therefore listed separately.) The minimum, maximum, and average time elapsed during the trajectories of these particles, as well as the standard deviation about the average time, are listed in the Min, Max, Avg, and Std Dev columns. This information indicates how much time the particle(s) spent in the domain before they escaped, aborted, evaporated, or were trapped.

 Fate                 Number           Elapsed Time (s)
                                     Min        Max        Avg    Std Dev
 ----                 ------  ---------- ---------- ---------- ---------- ---
 Incomplete                2   1.485e+01  2.410e+01  1.947e+01  4.623e+00
 Escaped - Zone 7          8   4.940e+00  2.196e+01  1.226e+01  4.871e+00

Also, on the right side of the report are listed the injection name and index of the trajectories with the minimum and maximum elapsed times. (You may need to use the scroll bar to view this information.)

   Elapsed Time (s)                       Injection, Index
 Min        Max        Avg    Std Dev                  Min                Max
 --- ---------- ---------- ---------- -------------------- ------------------
 +01  2.410e+01  1.947e+01  4.623e+00     injection-0    1   injection-0    0
 +00  2.196e+01  1.226e+01  4.871e+00     injection-0    9   injection-0    2

Mass Transfer Summary

For all droplet or combusting particles with each fate, the total initial and final mass flow rates and the change in mass flow rate are reported in the Initial, Final, and Change columns. With this information, you can determine how much mass was transferred to the continuous phase from the particles.

                   (*)- Mass Transfer Summary -(*)

 Fate                        Mass Flow (kg/s)
                           Initial      Final     Change
 ----                   ---------- ---------- ----------
 Incomplete              1.388e-03  1.943e-04 -1.194e-03
 Escaped - Zone 7        1.502e-03  2.481e-04 -1.254e-03

Energy Transfer Summary

For all particles with each fate, the total initial and final heat content and the change in heat content are reported in the Initial, Final, and Change columns. This report tells you how much heat was transferred from the continuous phase to the particles.

                    (*)- Energy Transfer Summary -(*)

 Fate                        Heat Content (W)
                           Initial      Final     Change
 ----                   ---------- ---------- ----------
 Incomplete              4.051e+02  3.088e+02 -9.630e+01
 Escaped - Zone 7        4.383e+02  3.914e+02 -4.696e+01

Combusting Particles

If combusting particles are present, FLUENT will include additional reporting on the volatiles and char converted. These reports are intended to help you identify the composition of the combusting particles as they exit the computational domain.

               (*)- Combusting Particles -(*)

 Fate              Volatile Content (kg/s)        Char Content (kg/s)
                    Initial      Final   %Conv     Initial      Final   %Conv
 ----            ---------- ---------- -------  ---------- ---------- -------
 Incomplete       6.247e-04  0.000e+00  100.00   5.691e-04  0.000e+00  100.00
 Escaped - Zone 7 6.758e-04  0.000e+00  100.00   6.158e-04  3.782e-05   93.86

The total volatile content at the start and end of the trajectory is reported in the Initial and Final columns under Volatile Content. The percentage of volatiles that has been devolatilized is reported in the %Conv column.

The total reactive portion (char) at the start and end of the trajectory is reported in the Initial and Final columns under Char Content. The percentage of char that reacted is reported in the %Conv column.

Combusting Particles with the Multiple Surface Reaction Model

If the multiple surface reaction model is used with combusting particles, FLUENT will include additional reporting on the mass of the individual solid species that constitute the particle mass.

               (*)- Multiple Surface Reactions -(*)

 Fate                 Species       Species Content (kg/s)
                        Names     Initial      Final   %Conv
 ----                 -------  ---------- ---------- -------
 Escaped - Zone 6        c<s>   6.080e-02  1.487e-06  100.00
 Escaped - Zone 6        s<s>   3.200e-03  5.077e-06   99.84
 Escaped - Zone 6         cao   0.000e+00  1.153e-03    0.00
 Escaped - Zone 6       caso4   0.000e+00  9.266e-04    0.00
 Escaped - Zone 6       caco3   8.000e-03  5.260e-03   34.25

The total mass of each solid species in the particles at the start and end of the trajectory is reported in the Initial and Final columns, respectively. The percentage of each species that is reacted is reported in the %Conv column. Note that for the solid reaction products (e.g., if the mass of a solid species has increased in the particle), the conversion is reported to be 0.


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© Fluent Inc. 2006-09-20