Head question

[csr17]

All,

I studied centrifugal pumps in university but other than that I have not worked with them in practice until now. I have a basic question about head.

Assume we have to pump a fluid vertically 10 ft and then horizontally another 10 ft. Ignore head loss and suction head for the purpose of this question. Is the head required simply 20 ft? Is the horizontal section treated no differently? I ask because every discussion of head uses the example of pumping a fluid straight up only. A horizontal section is seemingly never mentioned. Am I overthinking this?

Thanks

 

[EmmanuelTop]

If you ignore head losses, then the required head is only 10ft. Horizontal section does not come into play, because it is horizontal.

Things can get a bit more complicated if there are multiple uphill and downhill sections on discharge of the pump.

Dejan IVANOVIC
Process Engineer, MSChE

 

[LittleInch]

Don't ignore anything.

The head required to get flow is 10 ft PLUS the friction losses in your 20ft of pipe PLUS whatever pressure/head you want at the end of your pipe. Think of this in different ways, what if your vertical lift was 100 ft, but the horizontal bit 1000ft?

The issue over vertical upwards only is simply to get people to envisage what"head" means. You can think of it as a pipe with a tee off the main pipe which is actually flowing.

The key thing to understand about centrifugal pumps is that the head it gives out at the same speed is the same regardless of the liquid in it. Thus the PRESSURE is dependent on the liquid density.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bimr]

Head is the height at which a pump can raise water up.

http://www.eng-tips.com/

If you ignore the pipe friction loss (vertical and horizontal), then the required head is 10 ft.

If you want water flow at the 10 ft elevation, your pump will have to have at least 10 ft of head plus the friction loss (over the 20 ft of pipe) to get flow at the 10 ft high discharge point.

 

[csr17]

Great, that makes sense. Thanks guys.