Negative Static Pressure on fully closed globe valve

Tarmizi
Tarmizi Altair Community Member
edited July 2021 in Community Q&A

I am trying to simulate fully closed globe valve using BC as follow

- Inlet at 1.8288m/s

- Non slip wall fluid solid interface

- Initial temp at 298K

- Realizable k-epsilon

I get the result but it show the negative pressure for the whole domain. What does this mean? Is this logical? If not, anyone know why this happen and how to fix this?

image

Answers

  • acupro
    acupro
    Altair Employee
    edited July 2021

    Not quite sure what you are trying to simulate with this.  You indicate you have a defined velocity inlet - but no outlet.  This is generally speaking (constant properties, non-deforming structure) a non-physical setup, with no solution.  What are you expecting to see with this?

  • Junta_20361
    Junta_20361 New Altair Community Member
    edited July 2021

    Are you trying to simulate closing valve?

  • Tarmizi
    Tarmizi Altair Community Member
    edited July 2021

    Are you trying to simulate closing valve?

    not closing the valve but instead i want to simulate the valve in closed condition

  • acupro
    acupro
    Altair Employee
    edited July 2021
    Tarmizi said:

    not closing the valve but instead i want to simulate the valve in closed condition

    Again - where do you expect the incoming fluid (defined velocity inlet) to go, given there is no outlet?  What phenomenon/event/behavior in the real-world device would you like to model with simulation?

  • Junta_20361
    Junta_20361 New Altair Community Member
    edited July 2021
    Tarmizi said:

    not closing the valve but instead i want to simulate the valve in closed condition

    If the valve is closed >> so there will be no fluid coming in the domain >> no inlet velocity.

    I think you are trying to simulate a fluid static phenomenon not fluid dynamic.

    Do you want to calculate the pressure on valve wall and from that to calculate the stress/strain on the valve?

  • acupro
    acupro
    Altair Employee
    edited July 2021
    Tarmizi said:

    not closing the valve but instead i want to simulate the valve in closed condition

    Are you trying to see what happens when the pipe is empty of the liquid (initially filled with air, for example), then the liquid enters at the given velocity (or pressure) and rapidly exerts pressures/forces on the pipe and valve due to the valve being closed - after which the entering flow stops since there is no exit?