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-   -   how to set delta p in fluent ? (http://www.cfd-online.com/Forums/fluent/110826-how-set-delta-p-fluent.html)

malay December 21, 2012 13:54

how to set delta p in fluent ?
 
Hi all ....
I want to set a delta P ( \Delta P=1.3 Kpa ) , how can i do that in fluent ????

LuckyTran December 22, 2012 03:07

Quote:

Originally Posted by malay (Post 398602)
Hi all ....
I want to set a delta P ( \Delta P=1.3 Kpa ) , how can i do that in fluent ????

You must specify the inlet pressure and outlet pressure. Specifying only the pressure difference is not enough to establish all the necessary boundary conditions.

malay December 22, 2012 03:10

Quote:

Originally Posted by LuckyTran (Post 398633)
You must specify the inlet pressure and outlet pressure. Specifying only the pressure difference is not enough to establish all the necessary boundary conditions.

thanks for reply .... if i specify the inlet pressure 103 Kpa , and outlet o kpa , what is thw diffrence pressure ? i mean delta p ?

LuckyTran December 22, 2012 03:14

Quote:

Originally Posted by malay (Post 398635)
thanks for reply .... if i specify the inlet pressure 103 Kpa , and outlet o kpa , what is thw diffrence pressure ? i mean delta p ?

Then your difference in pressure is 103 kPa.

malay December 22, 2012 03:15

Quote:

Originally Posted by LuckyTran (Post 398636)
Then your difference in pressure is 103 kPa.

so what about operation pressure ???

LuckyTran December 22, 2012 03:22

Quote:

Originally Posted by malay (Post 398637)
so what about operation pressure ???

By default, when you specify pressure, it is the gage pressure that is specified. The pressure reference is the operating pressure. By default the operating pressure is 101.325 kPa.

When you specify the pressure to be 103 kPa and 0 kPa you are specifying that the absolute pressure is 103 kPa +101.325 kPa and 0 kPa + 101.325 kPa. For many incompressible flows the operating pressure has no influence.

Hope that helps.

malay December 22, 2012 03:24

Quote:

Originally Posted by LuckyTran (Post 398638)
By default, when you specify pressure, it is the gage pressure that is specified. The pressure reference is the operating pressure. By default the operating pressure is 101.325 kPa.

When you specify the pressure to be 103 kPa and 0 kPa you specifying that the absolute pressure is 103 kPa +101.325 kPa and 0 kPa + 101.325 kPa. For many incompressible flows the operating pressure has no influence.

Hope that helps.

thank you so much .....


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