An inward flow reaction turbine is required to produce a power of 280 kW at 200
rpm. The effective head on the turbine is 20 m. The inlet diameter is twice as the
outlet diameter. Assume hydraulic efficiency as 80%. The radial
velocity is 3.5 m/s and is constant. The ratio of breadth to wheel diameter is 0.1
and 5% of the flow area is blocked by vane thickness. Determine the inlet and
outlet diameters, inlet and exit vane angle and guide blade angle at the inlet.
Assume radial discharge.
External Dia =D1 =0.9m =D1=0.9m
Internal Dia =D 2 =0.45 =D2=0.45
Speed N=200rpm N=200rpm
Width at inlet B 1 =200mm=0.2m B1=200mm=0.2m
Velocity of flow vf 1 =vf 2 =1.8m/s
vf1=vf2=1.8m/s Guide blade angle α=10∘
α=10∘
Discharge at outlet = Radial
B=90∘
∴ B=90∘ and Vw 2 =0
The tangential velocity of the wheel at inlet and outlet are:-
=9.424m/s
=4.712m/s
ii. Absolute velocity of water at the inlet of the runner i.e. V1
from the
inlet velocity triangle.
ii. the velocity of whirl at inlet i.e. Vw1
=10.207m/s
iv. the runner blade angle means the angle and
from outlet velocity triangle we have
v. width or runner at outlet i.e. B2
=
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