-ve pressure

May 28, 2004, 00:09

Hi All

I am doing one simple simulation involving pressure calculations. But my problem is that I am getting -ve abs pressures at zones where there are high velocities (region of small gap).

I have tried refining the mesh. (all tets). But still I fail to get good solution. Kindly guide. Fluid is water. Pressure difference at inlet and outlet is 60psi(~4bar).

What shall I do?

thanks

May 28, 2004, 04:28

Are you sure that your flow is non-cavitating in the reality?

May 28, 2004, 08:27

Thanks Jörn

Right now I have no idea, but I have restarted the run with reduced pressure differential. This is working fine. Slowly I will ramp the pressure to my desired value. Lets see. Velocities go around 24m/s for water in 0.25mm gap. (where I get -ve pressure)

Anyway, if the flow is cavitating, what is the option? Shall I solve it with cavitation model?

May 28, 2004, 00:09	-ve pressure	#1
carno Guest Posts: n/a	Hi All I am doing one simple simulation involving pressure calculations. But my problem is that I am getting -ve abs pressures at zones where there are high velocities (region of small gap). I have tried refining the mesh. (all tets). But still I fail to get good solution. Kindly guide. Fluid is water. Pressure difference at inlet and outlet is 60psi(~4bar). What shall I do? thanks

May 28, 2004, 04:28	Re: -ve pressure	#2
Jörn Beilke Guest Posts: n/a	Are you sure that your flow is non-cavitating in the reality?

May 28, 2004, 08:27	Re: -ve pressure	#3
carno Guest Posts: n/a	Thanks Jörn Right now I have no idea, but I have restarted the run with reduced pressure differential. This is working fine. Slowly I will ramp the pressure to my desired value. Lets see. Velocities go around 24m/s for water in 0.25mm gap. (where I get -ve pressure) Anyway, if the flow is cavitating, what is the option? Shall I solve it with cavitation model?

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