confusion regarding geometry for CFD analysis

jeph91 · June 18, 2013, 03:47

Hello, im a beginner with fluent and other CFD softwares, I need to do CFD analysis of a packed bed reactor using Fluent but i have certain doubts regarding the geometry...the reactor is filled with a material in a compact manner so i decided to go with spheres packed together (hexagonally) in a cylinder but the actual particle size is very small and for that the geometry will be too complex in the sense spheres are too small to fit in a cylinder compactly and im not getting in what geometry they should be modeled.

So i want to know that if for a successful CFD analysis we need to go with the exact size of the particles. Please help.

michujo · June 18, 2013, 08:52

Hi. I agree with you. Modelling every single geometrical detail of the packed bed reactor is too expensive. I think that in these situations the reactor is modelled as a porous medium. I guess you'll need experimental measurements to relate the fluid flow with the pressure drop. Just google "cfd, packed bed reactor, porous media" or something like that.

That's just my guess. Hopefully some expert will contribute.

Cheers,
Michujo.

jeph91 · June 22, 2013, 17:33

thanks man..im concerned with how to put the particles in together...i heard some folks used algorithm to randomly generate spheres in a given geometry. but i cant do that...i have the particle size and void fraction and other data with me.

June 18, 2013, 03:47	confusion regarding geometry for CFD analysis	#1
jeph91 New Member Join Date: Jun 2013 Posts: 2 Rep Power: 0	Hello, im a beginner with fluent and other CFD softwares, I need to do CFD analysis of a packed bed reactor using Fluent but i have certain doubts regarding the geometry...the reactor is filled with a material in a compact manner so i decided to go with spheres packed together (hexagonally) in a cylinder but the actual particle size is very small and for that the geometry will be too complex in the sense spheres are too small to fit in a cylinder compactly and im not getting in what geometry they should be modeled. So i want to know that if for a successful CFD analysis we need to go with the exact size of the particles. Please help.

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June 18, 2013, 08:52		#2
michujo Senior Member Join Date: Dec 2011 Location: Madrid, Spain Posts: 134 Rep Power: 16	Hi. I agree with you. Modelling every single geometrical detail of the packed bed reactor is too expensive. I think that in these situations the reactor is modelled as a porous medium. I guess you'll need experimental measurements to relate the fluid flow with the pressure drop. Just google "cfd, packed bed reactor, porous media" or something like that. That's just my guess. Hopefully some expert will contribute. Cheers, Michujo.

June 22, 2013, 17:33		#3
jeph91 New Member Join Date: Jun 2013 Posts: 2 Rep Power: 0	thanks man..im concerned with how to put the particles in together...i heard some folks used algorithm to randomly generate spheres in a given geometry. but i cant do that...i have the particle size and void fraction and other data with me.