Species mass flow rate
Hello All,
I am trying to calculate the average mass flow rate of a particular species passing through a plane in the geometry, such as mass flow rate of CO2 passing through a plane. Can you please let me know if know how we can extract this information in paraview. Is there a way to calcualte this value directly in OpenFOAM Thanks, Nir |
Hi,
your post is old and you just made four posts so I think none will answer me. Do you find out how that works? If someone can explain it, it would be very good for me and all the others :) Tobi |
Hello Tobi,
How are you? I think I may be able to help you on this one. The most easy way to do this with paraView would be to calculate the total mass flow through a plane using Y_CO2*rho*U_n where U_n is the velocity component normal to the plane of interest and Y_CO2 is the mass fraction of CO2. If you have a plane not aligned with x, y or z, you can use the calculator filter or the surface flow filter to get the velocity components perpendicular to that plane. Make sure the calculator for rho*U_n works on the cell data. Than go to filters>integrate Variables and you will get a table with the integral Y_CO2*rho*U*dA over Area A. This is the mass of CO2 passing through the area. I do not have an example for doing this during the calculation, but I think something can be done with swak4Foam. Regards, Tom |
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I am fine. I have two weeks left to finish my masterthesis. Did you follow the libOpenSmoke thread? I find some fatal bugs in the tool and will bring out my updated model after I finished my thesis. So I think in 4 Weeks everything is avaiable (maybe + validation and description). To tool is very nice but there are some problems with the enthalpie. But I solved it :) Thanks for your replay. I am too stupid :) But I test it in the thermolibrary. therefor I ll create a new scalarField and will calculate the CO-emission in PPM directly. I think it should be possible :) and then I can compare it. Tobi |
Hi Tobi,
Yes I did follow the libOpenSmoke thread, looks like you have some interesting results! Quote:
good luck Tom |
Hi Tom,
one question to you. If I want the massweighted species in the whole fluid domain, is it possible to do like you said with mag(U) then? |
Hi Tom,
just one question, if I make everything correct. I wanna calculate CO in ppm on a patch. Therefor I calculate the Mean molmass with: M_aver = sum(Y_i / M_i) of CO, O2, H2O, N2, CO2, H2, OH After that I calculate CO in ppm like: COppm = M_aver/M_CO * Y_CO * 1.000.000 Well the temperature profil looks better with OpenFOAM compared with ansys but if I look to the CO emissions there is so a huge difference: Measurement 80 ppm Ansys 60 ppm OF 0.0013 ppm I am not sure if I make everything correct! |
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I would think you have: M_aver = sum(Y_i * M_i)/sum (Y_i) = sum(Y_i * M_i) and I agree with your calculation of COppm. Regards, Tom |
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thanks for your replay. I made a validation of my COppm calculation like I mentioned in the last post and its correct, like you told me :) In that case I realized a other bug in the thermodynamics :D but in my thesis there is no time for it. Maybe its a problem with the flameletgeneration. Tobi |
Hello,
Maybe a stupid thing to ask someone that is working on a thesis, but is ppm for gasses not volume based instead of mass based? best regards Wouter |
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ppm on (maybe) the species CO is based on the mol fraction [X_CO] * 1.000.000 = CO_ppm. If you wanna get an information on a slice its better to make a mass weighted calculation to get the better result. If you wanna get an information on a specified volume you should do a volume weighted calculation. If I am wrong please correct me. Greetings Tobi |
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Best wishes, Thomas |
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