Physics Help Forum surface tension and dropping (NEED HELP İN PROBLEM)

 Thermodynamics and Fluid Mechanics Thermodynamics and Fluid Mechanics Physics Help Forum

 Feb 4th 2016, 10:28 PM #1 Junior Member   Join Date: Feb 2016 Posts: 5 surface tension and dropping (NEED HELP İN PROBLEM) Hello friends; i want to solve the problem about surface tension and dropping. i find a equation on http://planetcalc.com/2296/ and i enter this formulato excel. But i dont sure this formula is true. http://picpaste.com/AdsAe_z-km3N3Ktc.jpg for water : if pipe outlet diameter is 9,45mm (or less) no dropping occuring cause of surface tension force. for oil : if pipe outlet diameter is 7,43mm (or less) no dropping occuring cause of surface tension force. Last edited by koytos; Feb 4th 2016 at 10:33 PM.
Feb 5th 2016, 06:18 AM   #2
Physics Team

Join Date: Jun 2010
Location: Morristown, NJ USA
Posts: 2,337
 Originally Posted by koytos Hello friends; i want to solve the problem about surface tension and dropping. i find a equation on http://planetcalc.com/2296/ and i enter this formulato excel. But i dont sure this formula is true. http://picpaste.com/AdsAe_z-km3N3Ktc.jpg for water : if pipe outlet diameter is 9,45mm (or less) no dropping occuring cause of surface tension force. for oil : if pipe outlet diameter is 7,43mm (or less) no dropping occuring cause of surface tension force.
I get different results: R = 3.34 mm for water and 2.63mm for oil. I think in your Excel calculation you forgot the 2 in the denominator of the equation.

And the interpretation of R is it is the maximum size of pipe that will allow dripping, as opposed to continuous flow. For pipes of smaller radius you get drops, for pipes of larger radius you get continuous flow (according to the author).

 Feb 5th 2016, 07:12 AM #3 Junior Member   Join Date: Feb 2016 Posts: 5
 Feb 15th 2016, 02:58 AM #4 Junior Member   Join Date: Feb 2016 Posts: 5 how can i calculate this system if the outlets are like in the picture? 5 different outlets 1- elips 2- square 4-circle 5- circle (but it has a filter) Attached Thumbnails   Last edited by koytos; Feb 15th 2016 at 03:01 AM.
 Feb 21st 2016, 11:58 PM #5 Junior Member   Join Date: Feb 2016 Posts: 5 if you dont understand clearly, please write.
 Feb 22nd 2016, 06:31 AM #6 Physics Team     Join Date: Jun 2010 Location: Morristown, NJ USA Posts: 2,337 Given that the formulas for this type of thing are empirical, I think you would have to try some experiments with these shapes and see what you get. But a reasonable estimate might be to use the distance from the centroid of each shape to the furthest part of the perimeter as the equivalent of radius in the formula. Last edited by ChipB; Feb 22nd 2016 at 06:33 AM.
Feb 26th 2016, 03:35 AM   #7
Junior Member

Join Date: Feb 2016
Posts: 5
 Originally Posted by ChipB Given that the formulas for this type of thing are empirical, I think you would have to try some experiments with these shapes and see what you get. But a reasonable estimate might be to use the distance from the centroid of each shape to the furthest part of the perimeter as the equivalent of radius in the formula.
thank you.

 Tags İn, dropping, problem, surface, tension

 Thread Tools Display Modes Linear Mode

 Similar Physics Forum Discussions Thread Thread Starter Forum Replies Last Post ling233 Thermodynamics and Fluid Mechanics 0 Feb 24th 2016 03:55 AM Xenophilius Thermodynamics and Fluid Mechanics 3 Oct 3rd 2011 02:21 AM asdfgh Advanced Optics 1 Feb 18th 2011 02:41 AM xtheunknown0 Kinematics and Dynamics 2 Sep 16th 2010 12:38 AM r.samanta Thermodynamics and Fluid Mechanics 1 Oct 18th 2009 08:44 AM