Page 322 - Fluid Mechanics and Thermodynamics of Turbomachinery

Hydraulic Turbines 303
4.0

2.0
Kaplan turbines

1.0
Cavitation coefficient, s 0.4 No cavitation

region

0.2
Francis turbines Severe

0.1 cavitation
region

0.04

0.02
0.1 0.2 0.4 0.6 1.0 2.0 4.0 6 8 10
Power specific speed, W (rad)
sp
FIG. 9.19. Variation of critical cavitation coefficient with non-dimensional specific speed
for Francis and Kaplan turbines (adapted from Moody and Zowski 1969).

0.8
Vapour pressure as head of water, m 0.6

0.4

0.2

0 10 20 30 40
Temperature, °C
FIG. 9.20. Vapour pressure of water as head (m) versus temperature.