Velocity Effect on Pumping

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RAKESH REDDY Associate Join Date: May 2011 Posts: 38 Good Answers: 1	Velocity Effect on Pumping 01/18/2012 6:21 AM
	Dear All, What will be the effect of Fluid Velocity on sizing pipe? if Velocity increases the friction losses increases because Friction loss = flv² / 2gd where v is velocity so velocity increases friction loss will also increase. But when calculating pipe size why there is a limitation of velocity ( 0.5-0.9 m/s for pump suction and 0.9 - 1.5m/s for pump discharge). If I increase the velocity at pump suction and getting sufficient suction head as per pump manufacturer recommendation and in the same way if I increase the velocity at pump discharge and select a pump with higher Head will it be a safe design? Kindly clarify me Regards, Rakesh
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PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32175 Good Answers: 839	#1 Re: Velocity effect on pumping 01/18/2012 6:47 AM
	Suction sizing is chosen to limit the risk of cavitation. Discharge sizing is chosen to optimise pumping costs vs installation costs. In general, if a liquid velocity exceeds 3m/s, then the pipe is too small. Plus! Most pump manufacturers have already done the sums. Next! __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
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Mukesh0861 Power-User Join Date: Dec 2010 Posts: 377 Good Answers: 20	#2 Re: Velocity Effect on Pumping 01/20/2012 10:59 AM
	In your question, you said friction losses increases with increase in velocity, then why you intend to increase velocities of your pump flow. You will increase your running losses, that means pump efficiency will also be poor and you will put your pump on cavitation risk.
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MarkhamCornoit Associate Join Date: Feb 2012 Posts: 37	#3 Re: Velocity Effect on Pumping 03/07/2012 12:26 AM
	The pressure returns to ambient only when the velocity returns to back to ambient. I think, the most common effect will be the velocity will be converted into pressure.
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