Pump flow rates,pump laws and calculating pressure drop/loss

[mm391]

Can anyone please help?

We have the flow rate of a pump in order to move fluid round a system. I was wondering what other information I would need in order to work out what the system pressure loss will be so we can size the pump head? Do pump laws or fan laws help? If so can someone please help me understand?

Many thanks

MM

 

[MFJewell]

Open a fluid mechanics book.

You need line size and length, size and number of fittings (valves, elbows, tees, reducers, etc.), elevation of suction and discharge points (not sure from your post if it is an open or closed system), pressure at suction and discharge points, and friction factor for piping material.

 

[LittleInch]

MFJ has it right.

Pump "laws" don't help.

note that pumps are differential devices, so information about the pressure, head and vapour pressure of the inlet is just as important about understanding what the outlet head needs to be to move your particular fluid through your system, i.e. all frictional losses and static values (positive or negative) that exist on your outlet system.

So you need all those things MFJ states plus flow rate, fluid properties (density, viscosity etc), type of pump and what the operating system will be.

You say "pump" which is normally for liquids, but then mention fan laws which are usually air or a gas of some sort.

Very vague question.

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

 

[Artisi]

Lesson 1 of basic hydraulic class 101.
Search the net, enough information there to keep you entertained for a few days, plus you might come to understand some of the basics.

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.)

 

[hydtools]

Hydrodynamic or positive displacent? And what previous responders say.

Ted