[malay]

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

[LuckyTran]

Originally Posted by malay

Hi all ....
I want to set a delta P ( 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]

Originally Posted by LuckyTran

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]

Originally Posted by malay

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]

Originally Posted by LuckyTran

Then your difference in pressure is 103 kPa.

so what about operation pressure ???

[LuckyTran]

Originally Posted by malay

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]

Originally Posted by LuckyTran

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 .....

[Gkchpa]

Originally Posted by LuckyTran

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

Hi Lucky tran , I am running a simulation using delta pressure of Fan ( fan pressure rise), I gave inlet and outlet pressure conditions but didn't didn't get the exact result , so as you mentioned here "Specifying only the pressure difference is not enough to establish all the necessary boundary conditions" what does it mean ?, Do i need to give any extra boundary conditions ?for fan apart from speed (RPM)

Thank You