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M. A. Rakib May 31, 2000 03:29

mixing determination
I am using FLUENT 5 for mixing simulation. I want to quantify mixing by injecting pulse tracer and then track the transient spread of these tracers. I want the concentration of these tracers at different locations in a flow domain. Can you please comment on how I can achieve this. I dont want to see the pathlines only., but to define an injection, with a known number of particles and then find out the tracer concentration concentration at different positions. I would be very grateful

fouzy June 1, 2000 14:26

Re: mixing determination

May be you can use discrete phase modeling like in combustion of coal. you can look in tutorial 2 of fluent 5 how to use a discrete phase model like in coal combustion. You can always use PDF method in this case if you have turbulent incompressible flow

best regards

John C. Chien June 1, 2000 21:17

Re: mixing determination
(1). You can try to use the temperature field to track the effect of mixing. (2). The energy equation is always available, and it has both the convection and diffusion effect. (3). It is hard to make the particle to show the effect of diffusion. The graphical particle path follows only the velocity field, so, no diffusion is included. (4). So, I think, it is much easier to track the temperature field to see the degree of mixing.

M. A. Rakib June 3, 2000 03:40

Re: mixing determination,thanks fouzy
Thank you. Can you suggest how I can define the tracer injection as follows: -- ~100 tracers injected at the inlet. -- 50% of these tracers, i.e. 50 tracers are colored black. -- Rest 50%, i.e. 50 tracers are differently colored, viz. gray.


M. A. Rakib June 3, 2000 03:48

Re: mixing determination, thanks John
Thanx. I used this method of mixing determination for two different streams being mixed. But I am exploring the case when the same fluid is being taken out and circulated back. For this case I have to take help of tracers. Now I want to use color coding. Can you please suggest how I can define the injection color. e.g. I want 50% of the tracers black, and 50% gray.

fouzy June 3, 2000 10:22

Re: mixing determination,thanks fouzy

May be you can use model with species but you will don't turn on the reactions models. so you will create two species in the panel of material that they have differents properties,and in the boundaries inlet you specifie the mass fraction for the two species, so you can track them after. or you can use dispersed model with two types of particules that des have differents shapes or density.

best regards

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