combining flows and pressures at a single point
combining flows and pressures at a single point
(OP)
If i have 2 seperate pipes combining at one common point in the system what will happen to the flow and pressure at that point
i have one pump on one line pumping at say 2l/s@ 2 bar and another pump in the second line pumping at 4l/s @ 1 bar, when the combine at the common point what will the resultant flow and pressure be?
Will one pump stop the other from pumping?
i have one pump on one line pumping at say 2l/s@ 2 bar and another pump in the second line pumping at 4l/s @ 1 bar, when the combine at the common point what will the resultant flow and pressure be?
Will one pump stop the other from pumping?





RE: combining flows and pressures at a single point
You have to guess a combined flowrate and calculate the pressure drop from the point of combination to the point of known pressure. Now you know the pressure at the merge point. Check the flow each pump would give against that pressure and compare the total flow with your guessed flowrate. Adjust your guess and repeat until the guess and the calculation are equal.
Katmar Software
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RE: combining flows and pressures at a single point
Without going through the maths for your particular situation (as there isn't enough information), it is quite possible for one pump to stop the other from pumping.
Patricia Lougheed
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RE: combining flows and pressures at a single point
What type of pumps are these? Centrifugal, or positive displacement?
RE: combining flows and pressures at a single point
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"Pumping accounts for 20% of the world's energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: combining flows and pressures at a single point
At this stage the crystal ball is foggy.
RE: combining flows and pressures at a single point
Best regards
Morten
RE: combining flows and pressures at a single point
1) Calculate the pressure drops from the pumps to where they combine flow
2) Add the pressure drop to each pump curve, and lay both of them over the system curve.
3) Where the pump with the higher discharge (call it pump 1) pressure meets the system curve, note the capacity and pressure.
4) Retrace the curve on pump 2 until you reach the pressure noted from where pump 1 intersects the system curve.
5) Add these capacities, and you should have a good idea of flow conditions at the point where they connect.
However, there are so many models involved, I would not consider this anymore than an estimate.
Any thoughts?
RE: combining flows and pressures at a single point
Any thoughts? "
Yes, physically measure the pressure at the common point as noted in my earlier post.
RE: combining flows and pressures at a single point
cams1975, check this out
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"Pumping accounts for 20% of the world's energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies) http://virtualpipeline.spaces.live.com/