Why pumps are generally less efficient than turbines?
Answers
Explanation:
Pumps increases the energy of fuel whereas turbine decreases it.Hydraulically the pump in turbine mode will gave no more efficiency as they are capable of handling more fluid.A pump can get efficiency as high asa almost 90% but a turbine or compresser is nowwhere near as efficient.
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Centrifugal Pumps
Principles of Similarity
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Single stage Centrifugal Pumps
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Engineering › Fluid Mechanics › Machines › Pumps ›
Centrifugal Pumps
Velocity triangles, Manometric Head and Efficiency
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Contents
Introduction
Recuperators
Velocity Triangles
The Efficiency Of Centrifugal Pumps
Page Comments
Introduction
These can be regarded as the inverse of a reaction turbine in that they convert mechanical energy into a head of liquid. The flow is always outwards (Except for propeller pumps) and the pump must run full. This means that before use they need to be filled with liquid ("primed"). The suction lift is limited to avoid cavitation.
The centrifugal pump is inherently less efficient than a turbine because of smaller losses when converting pressure energy to kinetic energy than visa versa.
The rotating impeller creates a forced vortex in the passages of the pump and the efficiency depends largely upon the extent to which the high velocity head is converted to pressure head.
Please Note that this page has been edited and extra worked examples added. The new page is shown under the heading"Single Stage Centrifugal Pumps"
Recuperators
Vortex Chamber
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The gradual increase of area decreases the velocity of flow and increases the pressure. The losses are high due to eddy currents caused by the radial component of flow from the impeller. There is also an out of balance radial thrust.
Parallel Vortex Chamber
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