Question

For a single stage impulse turbine with a rotor diameter of 2m and a speed of 3000 rpm when nozzle angle is 20 degree, the optimum velocity of steam in m/s will be



334



356



668



711

Answer 1

334 cv braise spraying park

Answer 2

optimum velocity of steam is 668 m / s

given

diameter=2m

∅=20 degrees

w=3000rpm

to find

optimum velocity of steam

solution

• The steam is fed through one or different convergent-divergent nozzles which donot extend completely around the circumference of the rotor, so that only part of the blades is impinged upon by the steam at any one time.
• The nozzles  allow governing of the turbine by shutting  one or more

• the formula used is:

$u=\frac{v cosa}{2}$

$v=\frac{2u}{cosa}$

v = (2 × (πDN/60))/cos 20

• v=optimum velocity

• u=πDN/60

• a is the nozzle angle

• D is the  diameter of rotor

• N is the speed in rpm

v=(π × 3000) / (30 × cos20)

v=668 m/s

optimum velocity of steam is 668 m / s

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