buoyant jet

 Register Blogs Members List Search Today's Posts Mark Forums Read

 March 14, 2001, 09:03 buoyant jet #1 appleyy Guest   Posts: n/a Sponsored Links I want to know the steady concentration of a specie after it is injected from chimney into air,I think it isn't possible to define multiple species,but i don't know how to define material and operating condition,especially how to define the diffusivity of that specie,which I think is the most important parameter in diffusion.And from the caculation,I can only know the velocity of the mass instead of the concentration of it,what is the matter,is diffusion equation included in FLUENT? How can I see it? thank you for your help.

 March 28, 2001, 06:52 Re: buoyant jet #2 JJ Guest   Posts: n/a Hi there, Not sure if u hv found the answer to ur question, but thot I'll juz give u my 2cents worth of opinion all the same. Your problem is rather similar to mine. u hv to define the 2 materials. one, is air, and the other is the emmision from the chimney. U can then define multiple species by going to 'species' and enabling the multiple species button. After which, go back to the material panel and add in the above 2 materials.Define the properties of the mixture consisting of air and emmission. U can define ur diffusivity coefficient there. U can also input in an equation. For me, I use a constant diffusivity of 1e-08 (fluid), for gases, I would think it is in the range of 1e-5. U have to verify it. Hope it is helpful. Cheers JJ

 March 28, 2001, 19:57 Re: buoyant jet #3 appleyy Guest   Posts: n/a thank you very much.But why the solution is only resulted from convection diffusion instead of molecular diffusion.I want to know the mass concentration of the specie by both convection diffusion and molecular diffusion, how can I do with it? thank you again.

 March 29, 2001, 01:49 Re: buoyant jet #4 JJ Guest   Posts: n/a Hi, I'm not too sure I udst ur question. However, I would like to know how u verify that the diffusion was attributed to convection and not molecular? May I ask what is the difference in temp of the emmission from air? or the density difference? JJ

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post doug Main CFD Forum 10 October 16, 2013 00:47 jits_aps90 Main CFD Forum 1 July 29, 2009 06:31 Fred CFX 5 February 11, 2007 13:01 Fred Main CFD Forum 0 February 8, 2007 14:15 Qi Yuan FLUENT 0 February 13, 2001 07:49