Pipes carrying litre/min from A to B - HELP

[Ruffian]

I was unable to attend a class in which we learned this, so any explanation would be appreciated (working and answer would be appreciated).

If a pipe is of 150mm dia. is carrying 40 litres/min from a site and it is replaced by 2 100mm dia. pipes carrying the same volume, what difference does it make to the head required to pump it?


Thankyou.

 

[pixel01]

The cross section of the 150mm pipe is approximately double the 100mm pipe. So the two cases are equivalent. But the smaller the pipe the more resistance to the liquid motion so the second case, the pump must be stronger for the pressure drop is somewhat higher.

 

[tacman]

Hello,

Thank you for reaching out for clarification on this topic. I will do my best to explain it to you.

To start, let's define some terms to make sure we are on the same page. "Dia." is short for diameter, which is the measurement of a straight line passing through the center of a circle or sphere. In this case, the diameter of the pipe is 150mm or 100mm.

The term "head" refers to the pressure required to move water through a pipe. It is typically measured in units of length, such as meters or feet.

Now, to answer your question, replacing a single 150mm diameter pipe with two 100mm diameter pipes will actually decrease the head required to pump the same volume of water. This is because the total cross-sectional area of the two smaller pipes is larger than the single larger pipe. The larger cross-sectional area allows for a smoother flow of water, resulting in less resistance and therefore less pressure needed to pump the water through the pipes.

To calculate the exact difference in head required, we would need to know the length and material of the pipes, as well as the specific pump being used. However, in general, using two smaller pipes will require less head than using one larger pipe.

I hope this helps to clarify the concept for you. If you have any further questions, please don't hesitate to ask. Best of luck in your studies!