Multi Species Flows in a mixing tank

DrBidden · December 1, 2011, 21:03

Can FloEFD simulate the residence time of chlorine in a dosing tank and specify the contact time or residence time. Is there a metric or equivalent for this.

Boris_M · January 16, 2012, 16:49

Hello DrBidden,
basically you can simulate mixtures of fluids transiently and monitor the mass or volume fraction of a fluid and therfore know at what time the fraction has reached a certain value.
I don't really know what th contact time is or what it means. Maybe if you could explain what your task is, I could better judge if FloEFD can help you.
Something that might relate to what you need is the LMA (Local Mean Age) basically telling you how well a certain volume is vented, such as a room.

Regards,
Boris

DrBidden · January 16, 2012, 20:50

Hi Boris
Thanks for your reply. LMA would help I guess if that is a metric available in FloEFD. I do not have the HVAC module which probably includes this metric. I am doing a particle study and then doing a statistical analysis to obtain my own residence time criteria.

Boris_M · January 17, 2012, 02:51

Yes, LMA is available in FloEFD. You will have to go into the calculation control options and there you'll find it in the advanced tab. This needs to be switched on before calculating as it has to be calculated with the flow. Then you can select it after the solver is finished in the parameter list for visualization.
I think it should be available without HVAC module but I cant remember.
Another feature and better suitable than particles are the tracers. This is a new post processing feature which allowes you to calculate contaminant distribution in the post processing. It basically uses the existing flow field to calculate the distribution of a contaminant, also over time with a steady state simulation. But for that you'll need the HVAC module.

Boris

December 1, 2011, 21:03	Multi Species Flows in a mixing tank	#1
DrBidden New Member colin Join Date: Dec 2011 Posts: 10 Rep Power: 15	Can FloEFD simulate the residence time of chlorine in a dosing tank and specify the contact time or residence time. Is there a metric or equivalent for this.

January 16, 2012, 20:50	Thanks	#3
DrBidden New Member colin Join Date: Dec 2011 Posts: 10 Rep Power: 15	Hi Boris Thanks for your reply. LMA would help I guess if that is a metric available in FloEFD. I do not have the HVAC module which probably includes this metric. I am doing a particle study and then doing a statistical analysis to obtain my own residence time criteria.

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January 16, 2012, 16:49		#2
Boris_M Disabled Join Date: Jul 2009 Posts: 616 Rep Power: 24	Hello DrBidden, basically you can simulate mixtures of fluids transiently and monitor the mass or volume fraction of a fluid and therfore know at what time the fraction has reached a certain value. I don't really know what th contact time is or what it means. Maybe if you could explain what your task is, I could better judge if FloEFD can help you. Something that might relate to what you need is the LMA (Local Mean Age) basically telling you how well a certain volume is vented, such as a room. Regards, Boris

January 17, 2012, 02:51		#4
Boris_M Disabled Join Date: Jul 2009 Posts: 616 Rep Power: 24	Yes, LMA is available in FloEFD. You will have to go into the calculation control options and there you'll find it in the advanced tab. This needs to be switched on before calculating as it has to be calculated with the flow. Then you can select it after the solver is finished in the parameter list for visualization. I think it should be available without HVAC module but I cant remember. Another feature and better suitable than particles are the tracers. This is a new post processing feature which allowes you to calculate contaminant distribution in the post processing. It basically uses the existing flow field to calculate the distribution of a contaminant, also over time with a steady state simulation. But for that you'll need the HVAC module. Boris