Two Pumps at common point

[MKdx]

Hello

I have two pipes in parallel that combines at the same point in the system. A pump is connected at the start each pipe line. The two pumps are pumping different fluids with known densities. The flow rate on each pipe segment is known too. The pressure is known at all three points of interest on the pipes.

-- How can I find the fluids ratio at the common point or the mixed density?
-- Can any pump stop the other from pumping?

I am new to mechanics selflearning, all help and guidance is appreciated.

regards

 

[BigInch]

The mix downstream of the common point is the sum of the two pump mass flow rates. If pump A is flowing 5 kg/h and pump B is flowing 10 kg/h, total flowrate is 15 kg/h with the weight percent flow of product A, 5/15 *100 = 33%, B = 67%

Pump B may slow down, stop, or backflow, if the head produced by pump A - absolute value of head loss in pipe AC + absolute value of head loss in pipe BC > head produced by pump B, or v/v. Check valves downstream of each pump discharge would prevent backflow in one pump caused by the other.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[Artisi]

Many unknows at this stage to give any answer other than the combined flow will be whatever the flow rate is for each pump at the same pressure in the individual pipelines at the point of intersection where the 2 pumps come together.
You require a system resistance curve for each pump drawn across the individual pump performance curve to even get somewhere near to understanding what is likely to happen.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[DubMac]

If they are centrifugal pumps then you will have pump with higher head trying to "pump back into" the lower head pump. If the backflow is sufficient to shut an installed check valve, then of course you will lose all flow contribution from that pump.
Typically for parallel flow setup in centrifugal pumps, the pump curves must be very steep and should be same discharge pressure.

 

[DubMac]

Google Parallel pumping with centrifugal pumps; there is a plethora of technical articles on the subject.