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-   -   Grade efficiency curves in CFX (http://www.cfd-online.com/Forums/cfx/111485-grade-efficiency-curves-cfx.html)

sakurabogoda January 8, 2013 09:44

Grade efficiency curves in CFX
 
Dear All,

I want to obtain grade efficiency curves at inlet and outlet of my domain. Can anybody help me?

I am using LES for Lagrangian particle tracking.

I would be much grateful for your helps as I stuck on finding collection efficiency of my simulation.

ghorrocks January 8, 2013 18:18

What is a grade efficiency curve?

sakurabogoda January 8, 2013 22:13

Dear Glenn,

“When we obtain particle collection efficiency of a poly dispersed sample, there is a range of particle sizes, separate with varying degrees of efficiency. This variation in the efficiency is referred to as the Grade Efficiency Curve”.

In my simulation I have to obtain this grade efficiency curve.

Actually, still I could not find how to obtain the collection efficiency in particle tracking. I found User FORTRAN can use for this one, but stuck on this stage.

Do you have any idea on obtaining collection efficiency and grade efficiency curves?

I am really tired of this. Many thanks for your helps.

ghorrocks January 9, 2013 05:45

The solver should report particle fates by size group - it will tell you how many go out the outlet and how many got trapped. This sounds like what you need for a grade efficiency curve calculation.

sakurabogoda January 9, 2013 09:27

Dear Glenn,

Thanks a lot for the reply.

I have done a simulations in CFX-tutorial to understand particle flow and to find particle mass fractions @ inlet and outlet. (All were steady state simulations)

I found in output file, it gives only the mass fraction @ inlet and outlet.

For example, in the tutorial "11. Flow through a Butterfly Valve" Particle diagnostics as follows,

================================================== ====================
Particle Diagnostics
================================================== ====================

+--------------------------------------------------------------------+
| Particle Mass Flow Summary |
+--------------------------------------------------------------------+

Sand One Way Coupled
Inlet 1.0000E-02
Outlet -1.0000E-02

Sand Fully Coupled
Inlet 1.0000E-02
Outlet -1.0000E-02

+--------------------------------------------------------------------+
| Particle Momentum Flow Summary |
+--------------------------------------------------------------------+

Sand One Way Coupled X-Comp. Y-Comp. Z-Comp.
Inlet 0.0000E+00 0.0000E+00 4.1087E-02
Outlet 4.4985E-04 -1.9144E-03 -4.1069E-02

Sand Fully Coupled X-Comp. Y-Comp. Z-Comp.
Inlet 0.0000E+00 0.0000E+00 4.0947E-02
Outlet 1.0488E-03 -4.4581E-03 -4.0543E-02

+--------------------------------------------------------------------+
| Particle Forces on Walls |
+--------------------------------------------------------------------+

Sand One Way Coupled X-Comp. Y-Comp. Z-Comp.
Default Domain Default -1.1786E-04 -3.2385E-03 3.0524E-03
pipe wall -1.4197E-02 -3.0213E-03 3.1836E-04

Sand Fully Coupled X-Comp. Y-Comp. Z-Comp.
Default Domain Default -5.2943E-05 -4.0915E-03 3.7797E-03
pipe wall -1.2482E-02 -2.6480E-03 2.6313E-04

-----------------------------------------------------------------------
But in this tutorial it used poly dispersed sample, and only "mass flow" is given in output, no mass/diameter fractions.

I know in this tutorial, all particles should be escape from outlet. My simulation is a cyclone separator (by LES) and still I haven't done simulation on that. Because I am thinking about how to view inlet and outlet grade efficiency considering these tutorial examples.

Really appreciate your advises.

ghorrocks January 12, 2013 16:23

Have a look at the documentation, for particle diagnostics. I think you have to enable this in the output tab in CFX-Pre.


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