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Difference in total flux plot and concentration plot - convection diffusion problem
Posted Dec 15, 2011, 5:07 a.m. EST Fluid & Heat, Chemical Reaction Engineering, Results & Visualization Version 4.2a 0 Replies
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I created a simple long tube geometry (r =0.7mm, L =850mm) in 2D axis symmetric model. I solve it first for NS in stationary mode and then use the solution to solve the species transport equation in time dependent mode. I want to plot the concetration plot at the outlet of the tube with time. So, I take the line intergration from the derived values section and compute the surface integration for " C*pi*r^2 for time untill saturation is reached.
Now the volume of the tube is known and when I integrate the area over this curve by converting the time scale into volume scale by multiplying with the flow rate (ml/sec), the value should be exactly the same as the volume of the tube. But apparently this is not the case , the value comes more than the volume.
Now when I do the same by taking total flux at the outlet instead of concentration at the outlet, I get the correct volume.
Normally, the surface integration of concentration should give the average concentration at the outlet, but I dont understand why the volume of tube comes larger in this case . Does some one has similar problem ,, any help would be appreciated!
Thanks
Pranay
Hello Pranay Ghosh
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