4 replies to this topic

[atiq124]

Background:

I am planning to use some redundant tanks for fire-fighting water in case of emergency. 

The water flow rate is 100 m3/h into Tank 1 which is connected to other 5 tanks at the bottom as shown in the attachment. All pipe sizes are 3" SS schedule 40 expect the main connecting pipe at bottom which is 6" SS. Each tank size is 20 m3, 4 meter high and bottom pipe height is 0.5 m. All Tanks are vented to atmosphere. 

 

Question:

For continuous flow rate of 100 m3/h through the top of Tank 1, will all the tanks balance themselves or Tank 1 is going to overflow due to lower outlet flow rate ?

 

The purpose is to make sure that water flows by gravity form Tank 1 to all other tanks and it does not overflow. The bottleneck seems to be the 3" bottom pipes for the flow rate. 

Attached Files

•  Tanks.jpg   56.06KB   5 downloads

Edited by atiq124, 28 September 2015 - 05:37 AM.

[Bobby Strain]

We are unlikely to do your work for you. But, if you do some calculations, maybe someone will comment.

 

Bobby

[Narayanan.u]

It should not overflow. The pressure should balance in all tanks.

[samayaraj]

Hi,

 

When the level difference in first tank & other tanks reaches above 1.8 m, tank has sufficient head to deliver velocity more than 5.6 m/sec. This equals to near 100 m³/hr flow in 3inch 40S sch pipe. I did not consider the losses. If you add losses, and if the total head required higher than tank height, it will overflow. Else, it will not overflow.

Edited by samayaraj, 29 September 2015 - 12:05 PM.

[samayaraj]

If you consider, 6inch outlet from tank 1, min head difference required will be nearly 0.12m (without losses) corresponds to 1.5 m/sec velocity. This is nearly equal to 100 m³/hr in 6inch sch 40 pipe.