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sandy November 30, 2008 16:39

Flow depending on gravity
Hi All. I want to do the flow analysis of a package, where a viscos fluid has to travel only due to gravity.

The package is like a bottle which contains a viscos liquid.I know the outlet pressure and mass flow rate. The liquid flows with gravity. So now i want to optimize the hole dia so that i can achieve my outlet mass flow rate.

Thnx, Sandy

Alain F December 9, 2008 04:03

Re: Flow depending on gravity
Sound like it is a free surface flow problem. In this case EFD can't do the whole job since the level of the flow will vary with the flowrate and flowrate depends on flow level throught the pressure head.

If it is not you can have your result by applying a pressure drop accross the outlet equal to the pressure head.

If you have a free surface you can do the job with EXCEL : determinate the pressure drop coefficient of your outlet with EFD software or IDEL'CIK pressure drop reference book (if its geometry is simple). With the pressure drop coefficient you can calculate the massflow rate vs time with a simple integration.


Immurlnum January 17, 2009 10:26

Hi People!
Hello People,

I Just joined up and am trying edit my profile but i can't see the button!! probably staring me in the face lol

thanks guys

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