Thermal Engineering II Set 4

Mechanical Engineering

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This set of Thermal Engineering 2 Multiple Choice Questions & Answers (MCQs) focuses on Thermal Engineering II Set 4

Q1 | Steam turbine is classified on basis of
  • type of blades
  • exhausting condition
  • type of steam flow
  • all of the mentioned
Answer: all of the mentioned
Explaination:
steam turbines are classified by type of blades, exhausting condition, type of steam flow, division of steam flow, type of compounding.
Q2 | High pressure turbine is a Non-Condensing turbine due to                      
  • exhaust conditions
  • axial flow of the steam
  • pressure-velocity compounding
  • velocity compounding
Answer: exhaust conditions
Explaination:
for high pressure turbines exhaust conditions are controlled by regulating valve which makes them to come under the category of non-condensing turbines.
Q3 | Impulse blades are in the shape of
  • rain drop
  • circular
  • half moon
  • none of the mentioned
Answer: half moon
Explaination:
blades used in impulse turbines are half moon shaped because as steam enters the moving blade it pushes the blade forward.
Q4 | Astern turbines are used in                    
  • power generation
  • marine purposes
  • aircraft
  • none of the mentioned
Answer: marine purposes
Explaination:
astern turbines are those classified based on exhaust conditions and are used for marine purposes.
Q5 | Cross compound steam turbines are once used in                            
  • generation of electricity
  • marine ships
  • automobiles
  • none of the mentioned
Answer: marine ships
Explaination:
cross compound turbines are once used in marine ships before two stroke diesel engines.
Q6 | When steam reaches turbine blades the type of force responsible for moving turbine blades are                            
  • axial force
  • shear force
  • longitudinal force
  • none of the mentioned
Answer: axial force
Explaination:
axial force pushes the turbine blade forward and causes movement in turbine blade.
Q7 | Multi stage arrangement of turbines is called as                      
  • impulse turbine
  • reaction turbine
  • compounding
  • none of the mentioned
Answer: compounding
Explaination:
multi stage arrangement of turbines reduces the pressure loss and velocity losses and hence it is called as compounding.
Q8 | Compounding efficiency at low speed.
  • decrease
  • increase
  • maximizes
  • none of the mentioned
Answer: increase
Explaination:
even at low speeds velocity wastage is prevented and hence efficiency is increased.
Q9 | In velocity compounded turbines flow passage is from                          
  • moving blades to fixed nozzles
  • fixed nozzles to moving blades
  • fixed blades to moving nozzles
  • none of the mentioned
Answer: none of the mentioned
Explaination:
in velocity compounded turbines velocity drop is maintained in stages and hence reducing velocity loses. hence in velocity compounded turbines flow passage is from fixed nozzles to multiple rows of
Q10 | A velocity compounded impulse turbine is also called as                      
  • curtis wheel
  • pressure compounded
  • curtis wheel & pressure compounded
  • none of the mentioned
Answer: curtis wheel
Explaination:
velocity compounded turbines are invented by a scientist called curtis and hence it is named after his name.
Q11 | Reaction turbine is also called as
  • impulse turbine
  • curtis wheel
  • parsons turbine
  • none of the mentioned
Answer: parsons turbine
Explaination:
reaction turbine was invented by a scientist names parson and hence it was named after his name.
Q12 | A turbine comprising of fixed blades and moving nozzles is called as reaction turbines.
  • true
  • false
Answer: true
Explaination:
in reaction turbines the reaction produced when steam hits the turbine is also utilized to produce power output.
Q13 | Which of these is not an application of back pressure turbine?
  • desalination of sea water
  • filtration of water
  • process industries
  • petrochemical installations
Answer: filtration of water
Explaination:
the applications of back pressure turbine are desalination of sea water, process industries, petrochemical installations, district heating and also for driving compressors and feed pumps.
Q14 | Pass-out turbines are used in which of these cases?
  • relatively high back pressure
  • small heating requirement
  • only relatively low back pressure
  • both relatively high back pressure and small heating requirement
Answer: both relatively high back pressure and small heating requirement
Explaination:
pass-out turbines are used in cases of relatively high back pressure and small heating requirements. they are used in cases where a certain quantity of steam is continuously extracted from the turbine at an intermediate stage for heating purposes at the desired temperature and pressure.
Q15 | Heat exchangers are classified into how many categories?
  • 1
  • 2
  • 3
  • 4
Answer: 4
Explaination:
nature of heat exchange process, relative direction of motion of fluid, mechanical design of heat exchange surface and physical state of heat exchanging fluids.
Q16 | Based upon the nature of heat exchange process, the heat exchangers are classified into how many categories
  • 1
  • 2
  • 3
  • 4
Answer: 3
Explaination:
direct contact, regenerators and recuperators.
Q17 | The energy transfer between the hot fluid and cold fluids is brought about by their complete physical mixing in
  • direct contact heat exchanger
  • regenerators
  • recuperators
  • boilers
Answer: direct contact heat exchanger
Explaination:
in this type of heat exchanger,
Q18 | Which type of flow arrangement is this?
  • counter flow
  • parallel flow
  • regenerator
  • shell and tube
Answer: parallel flow
Explaination:
in this type of arrangement, the fluids enter the unit from the same side, flow in the same direction and leave from the same side.
Q19 | Which of the following is not an example of recuperators type heat exchanger?
  • automobile radiators
  • condensers
  • chemical factories
  • oil heaters for an aero plane
Answer: chemical factories
Explaination:
recuperators are not used in chemical factories.
Q20 | In how many categories heat exchangers are classified on the basis of direction of flow of fluids?
  • 4 categories
  • 3 categories
  • 2 categories
  • 1 categories
Answer: 3 categories
Explaination:
parallel, counter and cross flow.
Q21 | In how many categories heat exchangers are classified on the basis of physical state of heat exchanging fluids?
  • 1
  • 2
  • 3
  • 4
Answer: 2
Explaination:
condenser and evaporator.
Q22 | Which of the following operations occur in a vapour refrigeration cycle?
  • compression
  • cooling and condensing
  • expansion and evaporation
  • all of the mentioned
Answer: all of the mentioned
Explaination:
these are the processes which constitute the vapour refrigeration cycle.
Q23 | Compression can be
  • dry compression
  • wet compression
  • both of the mentioned
  • none of the mentioned
Answer: both of the mentioned
Explaination:
dry compression starts with saturated vapour and wet compression starts with wet vapour.
Q24 | Wet compression is preferred over dry compression.
  • true
  • false
Answer: false
Explaination:
dry compression is always preferred.
Q25 | Why is wet compression not preferred?
  • the liquid refrigerant can be trapped in the head of cylinder
  • this may damage the valves or cylinder head
  • liquid refrigerant can wash away the lubricating oil thus accelerating wear
  • all of the mentioned
Answer: all of the mentioned
Explaination:
these are the reasons why dry compression is preferred over wet compression.
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