Calculation of pressure drops through a spiggoted line

[dacre]

Hi,

I am trying to calculate the pressure drop through a spigotted slurry tailings pipeline. The line is approximately 1500metres long with a spigot every 2.25metres. Approximately thirty spigots can be opened at any one time and they discharge to atmospheric conditions. To size pumps I am assuming to pump to the furthest end of the line and discharge through the thirty spigots. The problem is how to define the losses of the system. I presume each of the closed spigots can be represented by the loss through dead branch equal tee (I am assuming this is worst case as most books only give a loss for an equal tee). However, what can be used to represent the loss through a spigot. I thought perhaps using a dead run tee, but I think it is too conservative. Also as the flow passes each open spigot it reduces so the losses through the rest of line would get marginally smaller. Could I assume that these losses are insignificant and that by pumping to the end of the line, the losses would make up for the minor losses across the spigots.

Anybody out there who might have previous experience?

 

[RWF7437]

Contact the manufacturer of the "spigots". They are essentially partly closed valves and have head loss vs flow characteristics which the manufacturer should be able to provide.

If not, test them yourself over a range of flows. It's easy to do.

Good luck