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# Flow Rate before / after pump

## Flow Rate before / after pump

(OP)
Assume the flow rate of the fluid is 1 m3/hr and there is 10% spill back. with a total of 1.1 m3/hr flow rate of fluid across the pump.
By referring to the image attached, can I say that the flow rate of fluid at B is the same with that at A (Inlet: 1 m3/hr)?
Appreciate if anyone answer my question.
Thank you.

http://files.engineering.com/getfile.aspx?folder=8...

### RE: Flow Rate before / after pump

Yes you can.

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

### RE: Flow Rate before / after pump

(OP)
May I know, can you be mentor as I still have a lot of question want to ask about.
Sorry.

### RE: Flow Rate before / after pump

They really need to be real life problems and not, as I suspect, student postings...

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

### RE: Flow Rate before / after pump

think you question is wrong, if you have 1 m3/h entering the pump at A and 10% spill-back then the discharge at B is 1m3/h less 10%. Where does the 1.1 m3/h come from - do you mean 1.1 m3/h entering the pump at A?

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.)

### RE: Flow Rate before / after pump

Artisi - 1 m3 enters, 1m3 leaves.

what is going through the pump and back in again between A and B could be anything greater than 1. The "spill back" [hate that term] goes back into the pump inlet so stays in the system.

for the time being he's chosen 1.1, but could be 5 for all the difference it makes...

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

(OP)
Thank you.

### RE: Flow Rate before / after pump

LKS, your diagram shows a bypass line around the pump.
Perhaps it is meant to represent internal recirculation, which occurs in some types of pumps, or perhaps it is meant to represent an external bypass line, sometimes used on centrifugal pumps to move the operating point of the pump for a couple of reasons, and which may be equipped with a control valve, not shown, or sized to control the flow naturally just by its geometry.

Also, points A and B both seem to refer to tee junctions, which in general have three associated flows, and it's not clear to which flow each of the letters refer.

We here could be more helpful to you if you provide a little background about your education level, experience level, and exactly what problems you are trying to solve. If you take some time to browse the site, you will notice that the best and most useful answers arrive most quickly in response to fairly detailed questions that provide answers to the first ten obvious questions that can be conjectured.

Thank you for your cooperation, and good luck.

Mike Halloran
Pembroke Pines, FL, USA

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