Tank Filling/Overflow of tank investigation 1

[DaEarl]

Greetings,
I am currently part of an investigation involving the overflow of a tank. The system is as follows: two tanks, each the same diameter and height, each containing water, are both connected by a 16" CS pipe (300ft.). Water is pumped into both tanks at a constant rate. Tank 1 at 7500gpm and tank 2 at 1100 gpm. Tank 1 has a water level of 27 ft. and tank 2 has a 24 ft. level. My task is to develop a timeline for the overflow of tank 1 to corroborate the story of the operator in charge of the tanks.

MY METHOD: 1)I developed an equation for the flow of water through the 16" pipe. I derived the equation by Bernoulli's equation. I wrote the flowrate of the water as a function of the difference in height b/w the tanks taking into account the friction factor (f), equivalent length of pipe (L), and the diameter (D). 2)I used the continuity equation to describe the net flow rate of each tank (Q1net=Q1in-Qpipe; Q2net=Q2in+Qpipe). 3)I divided each net flow rate for each pipe and then divided by the area of the tanks (Q1net/A). This value is then multiplied by a time interval (30s) which in turn returns a height change. I continued iterating for 30s intervals until tank 1 reaches the 40ft. level (overflow level).

QUESTION: Is this a reasonable solution to the problem?

Thanks,
Kyle

 

[DaEarl]

tbedford,

The only tank level I can be sure about is tank 2. At the refinery we use software called Exaquantum to trend process variables such as tank level for this case. For some reason there is no level gauge outfitted on tank1, the one that overflowed.

So yes, I am quite concerned that the operators are giving me questionable information and timeline. This also concerns our management.

I am only certain about tank 2 original level of 24 ft.

Kyle (MOUSA)

 

[BigInch]

This is where some good simulation work would come in handy. Set up what they say, run.. and it shows them how the results don't jive. Ask them if they were sure it happened like that and/or give them a chance to "add some details they hadn't thought about before".

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com