problem with eulerian scheme

zain ali · August 4, 2014, 15:32

hi ,
i'm trying to simulate airflow reactor using where the reactor are filled with water and air is injected in the almost middle of the column , here is my setting and problem description
model>euler>implicit
turbulence >k-epsilon>dispersed
i tried many cases for interaction , also solvers but it keep giving me revers flow !!
the boundary conditions for
air ( dispersed phase ) u=0.6m/s (Secondary phase )
air volume fraction = 1 cause only air is injected
no outlet in the system
also i used marked to inject the air with (0 volume fraction in the cell zone)

any suggestion plz
what is the wrong with my setting ?
which gives a reversed flow ??

CeesH · August 6, 2014, 04:56

Dear Zain,

How exactly are you simulating a reactor that has an inlet but no outlets? That doesn't work, right?

Where do you get the reversed flow? I guess for the air inlet your boundary condition is a velocity inlet - so I guess it is not there?

Best,
Cees

zain ali · August 9, 2014, 10:15

hi Cees
thanks for your reply
the revers flow happened in few cells after entrance
the reactor have only gas in and gas out and liquid are contained in the reactor
i figure out my mistake it was with the turbulence model i used dispersed model for multiphase and that mean the turbulence will be in the secondary phase and partially in the primary phase while i should use mixture where the turbulence happen in both phases by this setting the effect of gas phase will make the liquid move in the right direction .
thank you for your attention

cheers !

August 4, 2014, 15:32	problem with eulerian scheme	#1
zain ali New Member zain Join Date: Jun 2014 Posts: 4 Rep Power: 11	hi , i'm trying to simulate airflow reactor using where the reactor are filled with water and air is injected in the almost middle of the column , here is my setting and problem description model>euler>implicit turbulence >k-epsilon>dispersed i tried many cases for interaction , also solvers but it keep giving me revers flow !! the boundary conditions for air ( dispersed phase ) u=0.6m/s (Secondary phase ) air volume fraction = 1 cause only air is injected no outlet in the system also i used marked to inject the air with (0 volume fraction in the cell zone) any suggestion plz what is the wrong with my setting ? which gives a reversed flow ??

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August 6, 2014, 04:56		#2
CeesH Senior Member Cees Haringa Join Date: May 2013 Location: Delft Posts: 607 Rep Power: 0	Dear Zain, How exactly are you simulating a reactor that has an inlet but no outlets? That doesn't work, right? Where do you get the reversed flow? I guess for the air inlet your boundary condition is a velocity inlet - so I guess it is not there? Best, Cees

August 9, 2014, 10:15		#3
zain ali New Member zain Join Date: Jun 2014 Posts: 4 Rep Power: 11	hi Cees thanks for your reply the revers flow happened in few cells after entrance the reactor have only gas in and gas out and liquid are contained in the reactor i figure out my mistake it was with the turbulence model i used dispersed model for multiphase and that mean the turbulence will be in the secondary phase and partially in the primary phase while i should use mixture where the turbulence happen in both phases by this setting the effect of gas phase will make the liquid move in the right direction . thank you for your attention cheers !