Flow through a inline cylinder array

new2cfd · December 16, 2009, 12:18

Hi all,

First off I am new to cfd and this forum. My question pertains to Fluent and cfd in general I believe. I have been working on the problem of trying to resolve friction factors and Nusselt number for various inline tube array with 100<Re<1500. I have been working on the problem for some time with very little success. I have tried 2D single half cylinder with periodicity and symmetry, half tube arrays with 10 or more tubes with velocity inlets and pressure outlets significant inlet and exit lengths, and half tubes on top and bottom of a row of full tubes. The problem is the friction factor is not even close to experimental data. I have tried laminar, ke, ko Re stress, and LES all steady and unsteady. I have yet to find a cfd paper reporting these value and tout flow structure but not engineering values. Can these values be accurately resolved to 10-20% error, and if so can you give me some guidance/references for this?

Thanks
Jonathan

thecfduser · December 16, 2009, 20:47

Hi
1-are u sure that ure geometry is 2D???? (i mean the geometry used to get experimental data)
2-are u including buoancy effects????
3- Avoid symetrical and peridocal boundaries: ure geometry is symetrical, but not the flow, specially that u have buoyancy effetcs. I think is is the major problem....
4-Laminar solver and LES in 2D will not necesseraly give real results.

Regards

December 16, 2009, 12:18	Flow through a inline cylinder array	#1
new2cfd New Member Jonathan Join Date: Dec 2009 Posts: 1 Rep Power: 0	Hi all, First off I am new to cfd and this forum. My question pertains to Fluent and cfd in general I believe. I have been working on the problem of trying to resolve friction factors and Nusselt number for various inline tube array with 100<Re<1500. I have been working on the problem for some time with very little success. I have tried 2D single half cylinder with periodicity and symmetry, half tube arrays with 10 or more tubes with velocity inlets and pressure outlets significant inlet and exit lengths, and half tubes on top and bottom of a row of full tubes. The problem is the friction factor is not even close to experimental data. I have tried laminar, ke, ko Re stress, and LES all steady and unsteady. I have yet to find a cfd paper reporting these value and tout flow structure but not engineering values. Can these values be accurately resolved to 10-20% error, and if so can you give me some guidance/references for this? Thanks Jonathan

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December 16, 2009, 20:47		#2
thecfduser Senior Member karine Join Date: Nov 2009 Posts: 158 Rep Power: 17	Hi 1-are u sure that ure geometry is 2D???? (i mean the geometry used to get experimental data) 2-are u including buoancy effects???? 3- Avoid symetrical and peridocal boundaries: ure geometry is symetrical, but not the flow, specially that u have buoyancy effetcs. I think is is the major problem.... 4-Laminar solver and LES in 2D will not necesseraly give real results. Regards