Best efficiency point and operating point for pumps, Civil Engineering

Q. Best efficiency point and operating point for pumps?

In a pumping system, a system curve can be derived based on static head needed to lift up the fluid and variable head because of possible head losses. Pump curves that relate the performance of pumping to head against discharge can be attained from pump suppliers. When system curve is superimposed on the pump curve, intersection point is defined as operating point (or duty point). Operating point may not be essentially the same as best efficiency point. Best efficiency point is a function of the pump itself and it's the point of lowest internal friction inside pump at the time of pumping. These losses are persuaded by adverse pressure, shock losses and friction. 

Losses owing to adverse pressure gradient take place in pumps as the pressure of flow increases from inlet to outlet of pumps and flow travels from a region of low to high pressure. It causes the formation of shear layers and flow separation. Flow oscillation can also take place that accounts for noise and vibration of pumps. Effect of adverse pressure gradient is more substantial in low flow condition. 

For shock losses, they are persuaded when inflow into pumps isn't radial and comprises swirl. In an ideal situation, flow within the pump must be parallel to impellers such that flow angle is very close to impeller angle. Deviation of the above situation from design causes energy losses and vibration.

1627_Best efficiency point and operating point for pumps.png

Fig: A diagram showing point of best efficiency ≠ operating point

Posted Date: 8/8/2013 4:07:18 AM | Location : United States

Related Discussions:- Best efficiency point and operating point for pumps, Assignment Help, Ask Question on Best efficiency point and operating point for pumps, Get Answer, Expert's Help, Best efficiency point and operating point for pumps Discussions

Write discussion on Best efficiency point and operating point for pumps
Your posts are moderated
Related Questions
composition of cement in cover bag should be written or not/ If written which country uses ?please specify the name ?

Define the Highlights of Critical Path Method A network analysis technique used to predict project duration by analyzing which sequence of activities has the least amount o

Ask questiPermanent Way:on #Minimum 100 words accepted#

Abrasion Test:   This test is carried out on stones used as aggregates for road construction. The test result shows the suitability of stones against   the grinding action u

Temporary bench marks

Define the Approach Velocity Typical problems have negligible approach velocity.  v 1 = Q/A, where A = the cross-sectional area of flow in the channel. The value is not the ve

defference between direct and indirect ranging..

limitation in using with bitumen as watertight material

At what places deep foundation are made?

Explain the Strength Design (LRFD)   1. γ Factors are applied to loads and φ factors applied to resistance. 2. Unfactored service loads receive a load factor γ > 1.0