Question

While designing a Pelton wheel, the velocity of the wheel ‘u’ is

(where: K_u = Speed ratio, H = Net head of turbine, g = Acceleration due to gravity)
1. \(K_u \sqrt{gH}\)
2. \(2K_u \sqrt {gH}\)
3. \(K_u \sqrt{2gH} \)
4. \(2Ku \sqrt {2gH}\)

Answer 1

Correct Answer - Option 3 : \(K_u \sqrt{2gH} \)

Concept:

The velocity of water jet V through nozzle at inlet in case of a Pelton wheel is given by,

\(V = {C_v}\sqrt {2gH} \)

And, the velocity of the wheel U in case of a Pelton wheel is given by,

\(U = {K_u}\sqrt {2gH} \)

Where, V is the velocity of the water jet at inlet,

U is the velocity of wheel (or bucket),

C_v is the coefficient velocity (normally varies from 0.97 to 0.99 for Pelton wheel)

K_u is the speed ratio,

H is the net head available after accounting for all losses and

g is acceleration due to gravity.