TAGGED: cfd-dem, coupling, fiber, mass-flow-inlet-boundary-condition, rocky-dem
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October 14, 2024 at 11:11 amivan.beltracchiSubscriber
Hi everyone,
i'm doing some analyses in this geometry, to generate from the inlet (created with the red surface) some particles in order to settle them in the lower geometry.
I've also verified the correct import of .f2r file from fluent (with a CFD simulation) to Rocky.
The problem is that, while the analysis is running, i can't see in the 3D view the effective generation of fibers and a message occurs inside the simulation log section:Â
" .... particles had their release time delayed by: 0.025 due to an overlap detection on inlet.
The number of generated fibers needs to respect a specific percentage of volume and for this reason, i calibrated the inlet mass flow to generate a total amount of fiber during the injection time (imposed equal to the duration of the previous CFD simulation from fluent)
Could someone help me?Â
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October 16, 2024 at 8:21 pmLucas Bertollo BaggioAnsys Employee
Hello Ivan,
Â
Please check your particle size and orientation.
The fibers might be overlapping to the walls around the inlet.Â
- try to reduce the size significantly
- try to rotate the fibers in 90 dega
- try to put the surface outside the walls
Â
let me know if it worked.
Â
Best regards,
Lucas
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October 17, 2024 at 7:42 amivan.beltracchiSubscriber
Hi Lucas and thank you for your suggestions.
Basically the fibers are short, in fact they are faced cilindrical with a diameter of 0.2 mm and a vertical aspect ratio of 65 (so their length is 13 mm).Â
I'm trying to change their orientation respect to the global system, maybe along the X axis.Â
I would ask you an information for the mass flow value.Since that inside the domain I have a specified percentage of fibers to fill it with a certain time, how could you suggest me to calibrate the injection?
The cfd analysis lasts 17 seconds.
I don't know if I need to calculate by myself the effective massflow by Knowing the velocity from which the fibers are moving ( mass flow = area of inlet * velocity * density of fibers ) and after that deriving the total time ( Wich will be lower than 17 seconds) required to produce the total amount of fibers.
The second way that I thought is to apply an injection time equal to the cfd analysis (17 seconds) and calibrate the mass flow in kg/s in order to generate a total amount of fiber close to the 1.5% of the volume.
I'm waiting for some information,
Best regardsÂ
IvanÂ
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