# Calculating the air velocity and contaminants passing through a window

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 March 23, 2020, 07:19 Calculating the air velocity and contaminants passing through a window #1 Member   Ben Simpson Join Date: Dec 2019 Location: UK Posts: 32 Rep Power: 6 Hi, I am setting up a natural ventilation model using buoyantBoussinesqSimpleFoam in OpenFOAM-v1812. The model is currently a very simple box shaped room with a window on either side. My current task is to calculate/predict the air velocity and the total CO2 concentration passing through the windows into the room and also leaving the room. Could someone inform me of the method I should be using to accomplish this? I am happy to provide more information regarding my model set-up if needed. Thank you for any advise you can provide. Kind regards, Ben

 April 7, 2020, 11:33 CO2 implementation - help #2 New Member   Marlen Join Date: Dec 2019 Posts: 4 Rep Power: 6 Hi, I just saw your post and was wondering if you got any further on the implementation of CO2 in your model? I have to simulate natural ventilation as well and I am struggling with impleneting the CO2 relase of a person into the room. Any help is really appreciated.

 April 8, 2020, 10:02 CO2 Implementation #3 Member   Ben Simpson Join Date: Dec 2019 Location: UK Posts: 32 Rep Power: 6 Hi Marlen, I have CO2 implemented into my natural ventilation model. I did this by adding CO2 into the thermophysicalProperties file in the constant folder. Code: ```CO2 { specie { molWeight 44.01; } thermodynamics { Tlow 200; Thigh 5000; Tcommon 1000; highCpCoeffs ( 4.45362 0.00314017 -1.27841e-06 2.394e-10 -1.66903e-14 -48967 -0.955396 ); lowCpCoeffs ( 2.27572 0.00992207 -1.04091e-05 6.86669e-09 -2.11728e-12 -48373.1 10.1885 ); } transport { As 1.67212e-06; Ts 170.672; } }``` I need to sense check the thermodynamics and transport values. I created an inlet object at the surface of my person object. I set a CO2 concentration in a CO2 file in the 0 folder and set an air velocity in the U file. In the controlDict file I added a CO2 function in the functions section. Code: ```CO2 { type scalarTransport; libs ("libsolverFunctionObjects.so"); writeControl timeStep; writeInterval 1; active true; autoSchemes false; nCorr 0; resetOnStartUp false; field CO2; fvOptions { } }``` I haven't validated my model yet so I cannot be 100% sure that this is working as expected. Hopefully that helps. Regards, Ben