Multiple Choice Questions (MCQ) on Steam nozzles and steam turbines

Multiple Choice Questions (MCQ) on Steam nozzles and steam turbines

 

A steam nozzle covert

  1. heat energy of steam into kinetic energy
  2. potential energy of steam into kinetic energy
  3. kinetic energy of steam into mechanical energy
  4. heat energy of steam into mechanical energy

(Ans:a)

 

The smallest section in nozzle is known as

  1. throat
  2. venturi
  3. convergent
  4. divergent

(Ans:a)

 

Which of the following is not true for steam nozzles?

  1. In convergent nozzle there is divergent after throat
  2. Convergent-divergent nozzle has higher expansion ratio
  3. Convergent-divergent nozzle produces steam at higher velocities as compared to a convergent nozzle
  4. All of the above

(Ans:a)

 

Which of the following is true for steam flow through nozzle?

  1. The flow is assumed to be adiabatic
  2. The steam loses its pressure and heat while passing through nozzle
  3. The work done is equal to the adiabatic heat drop
  4. All of the above

(Ans:d)

 

The maximum velocity of steam at throat is

  1. {2(n/n+1) p1v1}^1/2
  2. {2(n/n+1) p1v1}^3/2
  3. {2(n/2n+1) p1v1}^1/2
  4. {2(n/2n+1) p1v1}^3/2

Where, n=1.135 for saturated steam and 1.3 for superheated steam. p1= initial pressure of steam, v1=initial volume of 1 kg of steam at pressure p1

(Ans:a)

 

The correct order in which energy is converted from one form to another, in steam power plant is

  1. Kinetic energy – potential energy – mechanical energy – electrical energy
  2. Kinetic energy – potential energy– electrical energy – mechanical energy
  3. potential energy – Kinetic energy –mechanical energy – electrical energy
  4. mechanical energy – potential energy – Kinetic energy –electrical energy

(Ans:c)

 

The steam turbine can be governed by the following methods except

  1. Throttle governing
  2. Nozzle governing
  3. By pass governing
  4. Reaction governing

(Ans:d)

 

In reaction turbine the fixed blade

  1. alter the direction of steam
  2. allow steam to expand to a larger velocity
  3. functions as same of nozzle
  4. All of the above

(Ans:d)

 

The following are the method for compounding except

  1. velocity compounding
  2. pressure compounding
  3. volume compounding
  4. reaction turbine

(Ans:c)

 

In velocity compounding, steam is passed through

  1. fixed nozzle-moving blades-fixed blades-moving blades
  2. fixed nozzle-moving blades-fixed nozzles-moving blades
  3. moving blades-fixed nozzles- fixed blades-moving blades
  4. fixed blades-moving blades-fixed nozzles- moving blades

(Ans:a)

 

In pressure compounding, steam is passed through

  1. fixed nozzle-moving blades-fixed blades-moving blades
  2. fixed nozzle-moving blades-fixed nozzles-moving blades
  3. moving blades-fixed nozzles- fixed blades-moving blades
  4. fixed blades-moving blades-fixed nozzles- moving blades

(Ans:b)

 

In pressure velocity compounding

  1. moving blades are used
  2. fixed nozzles are used
  3. fixed blades are used
  4. All of the above are used

(Ans:d)

 

Which of the following is a steam turbine?

  1. De laval
  2. Kaplan
  3. Francis
  4. Bulb

(Ans:a)

 

Maximum efficiency in impulse steam turbine is

  1. 2Cosα
  2. Cos2α
  3. Cos(α/2)
  4. Cos^2α

Where α is nozzle angle

(Ans:d)

 

Degree of reaction is given by

  1. Heat drop in moving blades / total heat drop in the stage
  2. Heat drop in fixed blades / total heat drop in the stage
  3. Heat drop in moving blades / Heat drop in fixed blades
  4. total heat drop in the stage / Heat drop in fixed blades

(Ans:a)

 

Maximum efficiency in reaction steam turbine is

  1. 2Cos^2α/(1+ Cos^2α)
  2. Cos2α/(1+ Cos^2α)
  3. Cos(α/2) /(1+ Cos^2α)
  4. Cosα/(1+ Cos^2α)

Where α is nozzle angle

(Ans:a)