Boiler and Steam Turbine

Heat is mainly transferred by conduction, convection and radiation in

• Insulated pipes carrying hot water
• Refrigerator freezer coil
• Boiler furnaces
• condensation of steam in a condenser

The shell diameter and length of locomotive boiler are

• 1.5 m, 4 m
• 1.5 m, 6 m
• 1 m, 4 m
• 2 m, 4 m

Which one of the following statements is not true for a supercritical steam generator?

• It has a very small drum compared to a conventional boiler
• A supercritical pressure plant has higher efficiency than a subcriticalpressure plant
• The feed pressure required is very high, almost 1.2 to 1.4 times the boilerpressure
• As it requires absolutely pure feed water, preparation of feed water is moreimportant than in a subcritical pressure boiler

The distinguishing feature of Velox boiler is that it

• Is drumless
• uses supersonic
• Operates under supercritical pressure
• uses indirect heating

For a single stage impulse turbine with a rotor diameter of 2 m and aspeed of 3000 rpmwhen the nozzle angle is 20 , the optimum velocity ofsteam in m/s is

• 314
• 356
• 668
• 711

In steam turbine terminology, diaphragm refers to

• Separating wall between rotors carrying nozzles
• The ring of guide blades between rotors
• A partition between low and high pressure sides
• The flange connecting the turbine exit to the condenser

A single-stage impulse turbine with a diameter of 120 cm runs at 3000 rpm.If the bladespeed ratio is 0.42 then, the inlet velocity of steam will be

• 79 m/s
• 188m/s
• 450 m/s
• 900 m/s

Which one of the following is used to bring down the speed of an impulse steam turbine to practical limits?

• Differential Gear
• Compounding of the turbine
• A large flywheel
• A gear box

Why is compounding of steam turbines done?

• To improve efficiency
• To reduce the speed of rotor
• To reduce exit losses
• To increase the turbine output

On Mollier chart, flow th rough t urbine is represented by'

• horizontal straight line
• vertical straight line
• straight inclined line
• curved line