# Question: a vertical axis kaplan turbine is to be designed for...

###### Question details

A vertical axis Kaplan Turbine is to be designed for an overall
head of 9 m, delivering 800 kW

at a rotational speed of 150 rev/min. The vanes and runner are to
be mounted in an annular

duct of outer diameter 2 m and inner diameter 0.8 m. There is to be
no exit swirl, and a draft

tube reduces the axial velocity by a factor of two. Making a
reasonable assumption for the

overall efficiency, estimate the required flow rate and hence the
flow angle at exit from the

vanes and the relative flow angles at inlet and exit for the
runner. The losses of total head are

estimated as:

(a) across the guide vanes, 6% of exit velocity head

(b) across the runner, 8% of the exit relative velocity head

(c) in the draft tube, 20% of the change in the velocity
head.

Calculate the overall efficiency (for comparison with your
estimate)