2 replies to this topic

[Koffi]

Dear all,

I am faced with an interesting challenge with two surge tanks working in parallel. The challenge is to decide if a 4" interconnecting line can be used in place of a 20" interconnection between the two tanks, this interconnection is to keep the level of liquids in both tanks same at all times.

I am of the opinion that with a 4" line, the time required for liquid leveling in the tanks will be much longer than with a 20". However, I need to prove this with some calculation, does anyone have any experience of/ spreadsheet for this sort of hydraulic calculation?

The two tanks are not of same size, one has the following dimensions (ID=18m x H=17 ) while the other is (ID=30m x H=17 )

It basically boils down to determining how much time is required to balance interconnected fluids with different line sizes. Help anyone? Thanks

Regards,
Koffi.

[katmar]

You could do a rigorous calculation and work out the time for the tanks to balance if there is a given mis-match in their starting levels, but that doesn't give you the answer you need. What you really want to know is whether one of the tanks will overflow, or drain completely under operating conditions. You have to decide how much mis-match in the levels you can tolerate in normal operation and then design a system to suit. You need to take into account a lot more information than just the balancing line, and then do a complete hydraulic analysis. Off the top of my head, here are the things you need to consider (there may be more)

Do you feed into one tank, both tanks or into the balance line?
What are the average and peak feed flow rates?
Does the outlet come from one tank, both tanks or from the balance line?
What are the average and peak out flows?
Is the level in the surge tank(s) controlled? How?
What is the maximum allowable level in the tanks?
What is the minimum allowable level in the tanks?

[Koffi]

Thanks Katmar,

I really do appreciate your input and perspective and I am making progress with the calculation now.