AnsweredAssumed Answered

Creating Suction/Vacuum in a venturi tube using FlowSimulation

Question asked by Eran Levi on Sep 1, 2010
Latest reply on Sep 3, 2010 by Rich Bayless

Hi all,


I have encountered a problem while trying to create a suction effect using a venturi tube.


I have attached several snapshots of the setting I chose, as well as some post-calculation snapshots.


I know that there might be a problem with the nozzle minimal diameter which is 4 mm (don't think water can really pass through...),


but it is the principle that I am trying to understand.


my working fluid is water at 50 degrees Celsius.


My goal is to lift water located at about 20-40 cm   below   the venturi nozzle, using a thin 5mm tube.


the pressure at the venturi tube entrance is 700 kPa ; the pressure at the entrance to the thin tube is  103kPa;


the flow rates should be:


16 liter/min at the entrance to the venturi ;  2 liter/min through the thin 5mm tube ; and of course 18 liter/min at the venturi tube outlet.


I have turned on gravity, and tried to run the simulation with Pressure Potential on and off, getting the same result:


When the water entering the venturi reaches the thin tube, it immediately falls down, instead of creating suction and pulling the water (which is located below) up...


I might be wrong here, but the calculation shows that in the throat the pressure drops to LESS than the pressure at the bottom of the thin tube, therefore, theoretically,


there should be a suction effect...


I am new to the flow simulation tool and therefore will be vary glad if anyone could help me.


Thank you very much in advance,