562 



HYDRAULICS AND ITS APPLICATIONS 



buckets must have a minimum value so that e/must be perpendicular 

 to d e. 



If then a straight line, b r a', be drawn to represent v, and if a right- 

 angled triangle, b' a' e', be described on b r a', the angle b r a' e' being 

 equal to a, the side a' e' will represent 2 u. In the case of a radial flow 



turbine the construction is modified as shown in Fig. 263 b, where c r b" 

 represents the relative velocity at exit. 



ART. 150. EFFECT OF CENTRIFUGAL ACTION. 



In an axial flow impulse turbine with radial vanes, centrifugal action 

 tends to heap up the water towards the outside of the buckets and so to 

 cause an unevenness of flow which militates against efficient working. 



Thus in Fig. 264 a particle of water entering at P (in plan) tends i 

 to follow a path P A instead of its actual path P B. The outer particles 



