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Pipe Load Dynamic Effect - Surge Load

Pipe Load Dynamic Effect - Surge Load

Pipe Load Dynamic Effect - Surge Load

(OP)
I am designing a reinforced concrete top slab for a 10ft diameter wet well. The top slab will support two axial flow pumps and 24" diameter pipes.

I can calculate the static condition loading, but am having difficulty figuring out a dynamic component.

When the pumps kick on and off; I believe I will have a 'surge load'. At at 26ft head, it looks like my flow rate will be about 8,000 gpm.

When the pump kicks on it probably will not be as big of a kick because the water column will slowly rise. I bet it will be significant when the pump shuts down though. The whole water column will reverse direction and shoot out the bottom (i assume).

Any input on where to find additional info? My fluids textbook (Mech of Fluids by Potter) doesn't seem to cover this.

Attached is an image of the setup.

Thank you.

RE: Pipe Load Dynamic Effect - Surge Load

You show a check valve which should prevent the water reversing beyond that point, you might get the water below that point draining back out.
First thing, check with the pump manufacturers and see if they have any input. If this is a normal application for the pump, they may have design recommendations for the forces on the pump cans.
If the pipe is full of water up to some point, and you start the pumps, that column of water accelerates. The kinetic energy you're adding to that water can't exceed the pump power output, so that should get you a maximum acceleration, from that, a maximum force. And I assume the power output of the pump at starting might exceed steady-state values.

RE: Pipe Load Dynamic Effect - Surge Load

(OP)
Thank you. Yes, there is a check valve at the top.

RE: Pipe Load Dynamic Effect - Surge Load

Not sure I 100% understand what is going on.....but it seems to me that if you have a maximum flow rate (along with static pressure), you should be able to get a load/reaction.

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