surface tension and dropping (NEED HELP İN PROBLEM)

Feb 2016
5
0
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:

ChipB

PHF Helper
Jun 2010
2,367
292
Morristown, NJ USA
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 2016
5
0
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)
 

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Last edited:
Feb 2016
5
0
if you dont understand clearly, please write.
 

ChipB

PHF Helper
Jun 2010
2,367
292
Morristown, NJ USA
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:
Feb 2016
5
0
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.