Brochure

1515
Figure 1.4: Velocity distribution in inlet.
Hub plate Hub
Trailing edge
Shroud plate
Leading edge
Impeller channel
(blue area)
Impeller blade
The impeller’s direction of
rotation
 Tangential direction
 Radial direction
 Axial direction
The impeller’s direction of rotation
Figure 1.5: The impeller components, definitions of directions and flow relatively to the impeller.
The design of the inlet aims at creating a uniform velocity profile into the
impeller since this leads to the best performance. Figure 1.4 shows an example of
the velocity distribution at dierent cross-sections in the inlet.
1.2.2 Impeller
The blades of the rotating impeller transfer energy to the fluid there by
increasing pressure and velocity. The fluid is sucked into the impeller at the
impeller eye and flows through the impeller channels formed by the blades
between the shroud and hub, see figure 1.5.
The design of the impeller depends on the requirements for pressure, flow
and application. The impeller is the primary component determining the
pump performance. Pumps variants are often created only by modifying
the impeller.