However, a marked asymmetry may persist in response to high velocity head
This feature, combined with the pump casing passageway design, which is proportioned so fluid maintains its velocity head
with minimal energy loss, contributes toward a more energy-efficient fluid delivery with lower input power required.
As a result, velocity head
increases with reduction of the static pressure head till total pressure boundary condition is met to be zero.
* All the energy (P) applied by any mixing impeller produces a pumping effect (Q) and a velocity head
(H), so that P [alpha] QH
Although the level of the transmission of energy to liquid through the impeller is almost similar with the variation in the amplitude of impeller angular oscillation, the transformation of energy from the pressure head to the velocity head
, which causes the transport of energy, is more successful at a larger amplitude.
A diffuser is a diverging passage in which the flow is decelerated and the reduction in velocity head
is converted to a rise in static pressure.
In addition, the velocity head
(kinetic energy of fluid flowing in the inlet system) must also be supplied.
If the bottom of the tidal channel is at elevation F, and a velocity head
h is required to move water at a certain speed v, over the flat, then the depth D, in the channel is:
In the diffuser type, the impeller is surrounded by stationary guide vanes, which gradually reduce the velocity of the liquid and convert velocity head
into pressure head before it enters the casing, eliminating radial hydraulic unbalance.
Large suction inlets lower the NPSHR since velocity head
and entrance losses are decreased.