Storage tank defect spray distance
Storage tank defect spray distance
(OP)
Dear,
I don't exactly know where to post this question, but as it actually is a fluid flow issue, I thought I post it here.
I have to calculate the spray distance resulting from a small defect (say 10 or 20 mm) in a storage tank shell.
My first assumption was to calculate the outlet velocity using the hydrostatic pressure:
velocity = (2*g*Head)^0.5
where Head = the liquid height above the defect
Then calculate the time it takes for gravitation to get the liquid down:
droptime = (2*height of defect / g)^0.5
Then using droptime * velocity to get the horizontal distance of the spray.
However if I compare my results to the example results I have from someone elses calculation my distances are much larger (about 1.6 times).
I know I calculated the distance with constant horizontal speed of the flow which may not be accurate.
Can any of you help me to get a more accurate calculation method for this problem?
I don't exactly know where to post this question, but as it actually is a fluid flow issue, I thought I post it here.
I have to calculate the spray distance resulting from a small defect (say 10 or 20 mm) in a storage tank shell.
My first assumption was to calculate the outlet velocity using the hydrostatic pressure:
velocity = (2*g*Head)^0.5
where Head = the liquid height above the defect
Then calculate the time it takes for gravitation to get the liquid down:
droptime = (2*height of defect / g)^0.5
Then using droptime * velocity to get the horizontal distance of the spray.
However if I compare my results to the example results I have from someone elses calculation my distances are much larger (about 1.6 times).
I know I calculated the distance with constant horizontal speed of the flow which may not be accurate.
Can any of you help me to get a more accurate calculation method for this problem?





RE: Storage tank defect spray distance
1. Pressure (if it's a pressurized tank, the velocity would increase, v = (2*g*Head + pressure/density)^0.5
2. Viscosity, if the fluid is more viscous than water then you may have more losses due to friction.
3. The calculation is assuming no losses occurring at the defect.
All in all, if you are wanting to find the worst case scenario, then your calculation (unless the tank is pressurized) are correct.
RE: Storage tank defect spray distance
Good luck,
Latexman
To a ChE, the glass is always full - 1/2 air and 1/2 water.
RE: Storage tank defect spray distance
@Latexman:
I didn't do anything more then using above three formulas (velocity = (2*g*Head)^0.5, droptime = (2*height of defect / g)^0.5 and distance=velocity*droptime) to calculate the distance for multiple defect locations. Then took the highest value from these calculations as maximum distance to be considered.
If there are any other factors I have/can take into account please let me know.
RE: Storage tank defect spray distance
Good luck,
Latexman
To a ChE, the glass is always full - 1/2 air and 1/2 water.