V = U
+ W
Note: Vector addition.
Construction
of the velocity diagram is a key step in the analysis.
Two
constructions are necessary: One diagram
for the entrance
to the vane and one for the exit from the
vane.
V =
absolute velocity of the fluid striking the turbine at entrance
U =
absolute velocity of the impeller taken at the entrance to the
vane and at the exit of the vane
W
= velocity of the fluid with respect to the vane on the impeller
Note: For an ideal pump the W doesn't change
along the vane.
It is the same for the inlet and for the
exit on the vane. |