STEAM TURBINES (PART - B)

The blade speed ratio of an impulse turbine is

• Blade velocity / Steam velocity at inlet

• Blade velocity / Steam velocity at outlet

• Air velocity / Steam velocity at inlet

• None of the above

In general, the flow through a nozzle is regarded as

• Isentropic

• Isobaric

• Isothermal

• Isochoric

In an impulse turbine, the steam is expanded in

• Moving blades only

• Nozzles only

• Both in fixed and moving blades

• None of the above

The shape of blades of …………. is of half-moon geometry

• Reaction turbine

• Impulse turbine

• Francis turbine

• Propeller

In case of an impulse turbine, complete pressure drop occurs in

• Nozzle only

• Moving Blades only

• Nozzle and Moving blades

• None of the above

Steam enters an impulse turbine at a velocity of 500 m/s and having nozzle angle 20 deg. The symmetrical blades have a mean peripheral velocity of 300 m/s. Consider a mass flow rate of 0.75 kg/s. Find the blade angle in degree, assuming the steam enters the blade without shock.

• 15.1

• 45.2

• 25.5

• 10.4

Steam enters an impulse turbine at a velocity of 500 m/s and having nozzle angle 20 deg. The symmetrical blades have a mean peripheral velocity of 300 m/s. Consider a mass flow rate of 0.75 kg/s. Calculate the tangential forces on the blades (N) for the turbine . Neglect friction effects on blades.

• 546.36

• 498.65

• 660.54

• 254.77

Steam enters an impulse turbine at a velocity of 500 m/s and having nozzle angle 20 deg. The symmetrical blades have a mean peripheral velocity of 300 m/s. Consider a mass flow rate of 0.75 kg/s. Calculate the diagram power (kW) for the turbine. Neglect friction effects on blades.

• 100.25

• 76.43

• 150.63

• 200.36

Steam enters an impulse turbine at a velocity of 500 m/s and having nozzle angle 20 deg. The symmetrical blades have a mean peripheral velocity of 300 m/s. Consider a mass flow rate of 0.75 kg/s. Estimate the axial thrust (N), assuming the steam enters the blade without shock.

• 0

• 0.01

• 0.15

• 1.52

Steam enters an impulse turbine at a velocity of 500 m/s and having nozzle angle 20 deg. The symmetrical blades have a mean peripheral velocity of 300 m/s. Consider a mass flow rate of 0.75 kg/s. Estimate the diagram efficiency (in %), assuming the steam enters the blade without shock.

• 79.65

• 81.52

• 80.65

• 91.65