Find the Perfect Drain Size for Your Cylindrical Tank | Flow Physics Assistance

[wat]

i need your urgent help in the following :

I have a cylindrical tank :
- inner diameter is 2 m
- capacity 50 m3
- hight over ground 0.5 m (50 cm) from ground to tank bottom

- the tank is 60% full of liqued and 40% gas , the pressure inside
the tank is 3 bar :

What is the drain size (diameter) that allow to get 2.8 m3/h of the liquid , without using any pumps , just by the pressure force inside the tank ?


and thanks for your help

 

[quark]

That is a funny tank, in practice. (16 m height / 2m dia.) Is it horizontal or vertical?

Just go to the link below and do some trials and error.
http://www.efunda.com/formulae/fluids/draining_tank.cfm#calc

Consider 3 bar as 30 meters head approximately. 60% liquid adds about 9 meters and initially the head will be 39 meters. As the tank gets emptied, the head will be 30 meters. The average of these two flow readings gives you the average flowrate.

The diameter is approximately 0.2mm

Use a rather conservative discharge coefficient of 0.85

 

[wat]

flow

many thanks for reply

the tank is horizontal , attached drawing is cross section in tank


and what is the effect of liquid viscosity ?


thanks again