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Old   July 12, 2004, 07:18
Default "Periodic" boundary
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Stex
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Hi, I'm studying the flow inside a single pipe heat exchanger. I use CFX with the "Periodic" boundary. After trying some value of "momentum source" I find the right one to carry out the mass flow I need. But after all I found a value of the pressure equal both on the inlet and outlet. So how can I calculate the Pressure Drop? Thank you very much.

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Old   July 12, 2004, 11:00
Default Re: "Periodic" boundary
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Derrek
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Define an expression such as "deltaP" = massFlowAve(ptot)@thenameofyourinlet -massFlowAve(ptot)@thenameofyouroutlet.

Then in the Output Control. Define a monitor point and define it as an expression = deltaP..

When you go to Post, you will have an expression defined that automatically calculates your pressure drop..

Derrek
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Old   July 13, 2004, 09:26
Default Re: "Periodic" boundary
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Stevie Wonder
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If you have a periodic BC, your local pressure drop in the streamwise direction is:
dp = p(PERIODIC PLANE1)-p(PERIODIC PLANE2)


If your periodic domain has 1m length, the pressure drop of 50m will be 50 * dp.


If you want to model pressure drop I think you should consider a domain with an inlet/outlet instead.
Good luck, Stevie Wonder
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