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Old   July 1, 2017, 10:09
Default Simple model not matching calculated values
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Hi,

I am doing a project for uni where I am trying to calculate the flow rate needed to create a certain pressure at the start of some pipework for a range of temperatures. The calculated values and real world test values show that when plotting temp against flow rate it should be a curve but the CFD values are coming out as a straight line.

I have simplified the model to just a small section of straight pipe with a 90 elbow and laminar model but results are still showing a straight line. At lower temps/higher viscosities (-10 to 5C) the calculated and CFD values match well but then when going to higher temperatures which is only from 5 to 20C they start to separate with the calculated values curving up and cfd values staying straight.

I know its bit of an open question but is there something simple I could be doing wrong? Its as if the software is ignoring the viscosity in some way.


Just to add to this. I have simplified it even further to just a straight pipe so that there isn't anything else to worry about like bends and it is still doing this


Thanks,

Nick

Last edited by Nick8529; July 1, 2017 at 10:23. Reason: more info
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