[Venkatsai]

I am doing flow simulation of centrifugal compressor
since my inlet and exit are very short, so i gave opening as boundary condition for inlet and outlet
but i was unable to understand what values should i define, and what options should i choose for opening boundary condition
so please could someone help me,

[ghorrocks]

You can only put boundary conditions at locations where you know the flow conditions. You then impose those flow conditions as a boundary condition on your domain. If you do not know the flow condition at a location then you cannot put a boundary condition there.

If you can explain what you do know about this device then we can try to help you select the correct boundary conditions.

[Venkatsai]

Thank you for your reply

I modelled centrifugal compressor in solidworks and i imported to cfx, now i want know how much pressure rise, this model can achieve at sea level conditions,
so what are the values that i need to define, and what options should i choose, if i keep opening as boundary condition at inlet and outlet
(like do i need to choose "static pressure and dir" or "opening pressure and dir"
say if i choose "opening pressure and dir", "opening temperature" then what value that i need to define for relative pressure , temperature etc )

[ghorrocks]

If you read the CFX documentation on Tips for selecting boundary conditions it describes the options and their advantages and disadvantages.