Question

The efficiency of an impulse turbine is maximum when (where Vb = Blade speed, V = Absolute velocity of steam entering the blade, and α = Nozzle angle)

a.

Vb = 0.5 V cos α

b.

Vb = V cos α

c.

Vb = 0.5 V2 cos α

d.

Vb = V2 cosα

Answer: (a).Vb = 0.5 V cos α

Interact with the Community - Share Your Thoughts

Uncertain About the Answer? Seek Clarification Here.

Understand the Explanation? Include it Here.

Q. The efficiency of an impulse turbine is maximum when (where Vb = Blade speed, V = Absolute velocity of steam entering the blade, and α = Nozzle angle)

Similar Questions

Explore Relevant Multiple Choice Questions (MCQs)

Q. In a nozzle, the effect of supersaturation is to increase the dryness fraction of steam.

Q. In an impulse turbine, steam expands

Q. In a 50% reaction turbine stage, tangential component of absolute velocity at rotor inlet is 537 m/s and the blade velocity is 454 m/s. The power output in kW of steam will be

Q. The process of draining steam from the turbine, at certain points during its expansion and using this steam for heating the feed water in feed water heaters and then supplying it to the boiler is known as

Q. Steam turbines may be classified according to

Q. Which of the following statement is wrong?

Q. If the critical pressure ratio for steam is 0.546, then the steam is initially

Q. The pressure velocity compounded impulse turbine allows a bigger pressure drop and hence __________ number of stages are required.

Q. Which of the following statement is correct?

Q. In a nozzle, the effect of supersaturation is to

Q. In a Parson's turbine stage, blade velocity is 320 m/s at the mean radius and rotor blade exit angle is 30°. For minimum kinetic energy of the steam leaving the stage, the steam velocity at the exit of the rotor will be

Q. The effect of friction in the nozzle __________ dryness fraction of steam.

Q. In a reaction turbine when the degree of reaction is zero, then there is

Q. The pressure compounded impulse turbine as compared to velocity compounded turbine require __________ number of stages.

Q. The maximum efficiency of a De-Laval turbine is (where α = Nozzle angle)

Q. For a Parson's reaction turbine, if α1 and α2 are fixed blade angles at inlet and exit respectively and β1 and β2 are the moving blade angles at entrance and exit respectively, then

Q. The critical pressure ratio for initially superheated steam is __________ as compared to initially dry saturated steam.

Q. The expansion of steam, as it flows over the blades in reaction turbine, represents

Q. The effect of bleeding is that

Q. The blade friction in the impulse turbine reduces the velocity of steam by __________ while it passes over the blades.

Recommended Subjects

Are you eager to expand your knowledge beyond Mechanical Engineering? We've handpicked a range of related categories that you might find intriguing.

Click on the categories below to discover a wealth of MCQs and enrich your understanding of various subjects. Happy exploring!