Category: Steam and Gas Turbines Objective Questions

Steam and Gas Turbines Multiple Choice Questions on “Usage of Cryogenics in Gas Turbines”.

1. In cryogenic rocket engines use oxidizer as fuel.
a) True
b) False
Answer: a
Clarification: In cryogenic rocket engines use oxidizer as fuel.

2. Cryogenic fuels are stored under _______ temperatures.
a) high
b) low
c) medium
d) none of the mentioned
Answer: b
Clarification: Cryogenic rocket fuels are stored under low temperatures. Cryogenics works under minus degree Celsius and hence they are stored in low temperatures.

3. Rocket engines require _______ mass flow rate.
a) high
b) low
c) medium
d) none of the mentioned
Answer: a
Clarification: Rocket engines require high mass flow rate. Rocket engines requires high thrust and for producing high thrust high mass flow rate is required.

4. Rocket fuels has ________ molecular weight.
a) medium
b) high
c) low
d) none of the mentioned
Answer: c
Clarification: Rocket fuels has low molecular weight.

5. Cryogenic fuels are in _________ state at room temperature and pressure.
a) gaseous
b) liquid
c) solid
d) none of the mentioned
Answer: a
Clarification: Cryogenic fuels are in a gaseous state at room temperature and pressure. Cryogenics work under low temperatures and when temperature is changed to room temperature then phase transfer takes place.

6. Cryogenic rocket engines are also called as hybrid rocket engines.
a) True
b) False
Answer: a
Clarification: Cryogenic rocket engines are also called as hybrid rocket engines.

7. Hybrid rocket engines are also called as ________ propellant rocket engines.
a) solid
b) liquid
c) solid & liquid
d) none of the mentioned
Answer: b
Clarification: Hybrid rocket engines are also called as liquid propellant rocket engines. Because fuels used in hybrid engines are in liquid state.

8. ____________ is used as cryogenic fuel.
a) Liquid oxygen
b) Liquid hydrogen
c) Combination of liquid oxygen and liquid hydrogen
d) None of the mentioned
Answer: a
Clarification: Combination of both liquid oxygen and liquid hydrogen are used as cryogenic fuel. Mixture of this liquid oxygen and liquid hydrogen results in low temperature which is a main property of cryogenic fuels.

9. Liquid hydrogen and oxygen mixture produces thrust upto ________
a) 5 Km/s
b) 4 Km/s
c) 4.5 Km/s
d) 5.5 Km/s
Answer: c
Clarification: Liquid hydrogen and oxygen mixture produces thrust upto 4.5 Km/s. Cryogenic fuels produce high thrust force.

10. _________ initiators are used in cryogenic rocket engines.
a) Pyrotechnic
b) Centrifugal
c) Pyrotechnic & Centrifugal
d) None of the mentioned
Answer: a
Clarification: Pyrotechnic initiators are used in cryogenic rocket engines.

Steam Turbine Interview Questions and Answers on “Heat and Steam Rate”.

1. Heat rate defines how much energy is to be expanded for obtaining a unit of useful work.
a) True
b) False

Answer: a
Clarification: Heat rate means the amount of energy that must be expanded for obtaining an unit of useful work.

2. What is heat rate in turbine?
a) Heat required for unit of power generated in specific conditions and specific fuel burning
b) Amount of heat required to expand turbine blades
c) Amount of heat required to increase pressure of steam
d) None of the mentioned

Answer: a
Clarification: Heat rate in turbines is defined as heat required to generate unit power in turbine at specific fuel being burned at specific conditions.

3. For calculating heat rate in steam turbines enthalpy is calculated.
a) False
b) True

Answer: b
Clarification: Heat rate can be calculated by using enthalpy method.

4. Steam turbine governing can be defined as __________
a) increasing the steam speed
b) adjusting the governors for particular speeds
c) controlling the flow rate of steam
d) none of the mentioned

Answer: c
Clarification: Governors are used to control the fuel needed to the load and they are no way related to the steam turbine governing. Steam turbine governing is controlling the flow rate of steam.

5. Why is steam turbine governing used?
a) To increase the steam speed
b) To maintain steam speed constant
c) To decrease the steam speed
d) None of the mentioned

Answer: b
Clarification: Flow rate if steam is controlled to maintain the constant speed.

6. In nozzle governing the flow rate is controlled by ____________
a) opening and closing the valves at nozzle
b) adding more number of nozzles
c) increasing nozzle efficiency
d) none of the mentioned

Answer: a
Clarification: Opening and closing of valves at nozzle is called nozzle governing.

7. During overload of turbines __________ are used.
a) throttle governing
b) nozzle valves
c) bypass governing
d) none of the mentioned

Answer: c
Clarification: During overload conditions fresh steam is added into later stages called as bypass governing.

8. When is emergency governing used?
a) Speed of shaft increased above 110%
b) When turbine is shut down due to overload
c) When Low steam is entering
d) None of the mentioned

Answer: a
Clarification: When speed of shaft is increased to 110% then emergency governing is used to control the speed.

9. When balancing of the turbine is disturbed ___________ is used.
a) Potter governor
b) Centrifugal governor
c) Emergency governor
d) None of the mentioned

Answer: c
Clarification: Emergency governor is also used when balancing of the turbine is disturbed.

10. When lubrication is failed _____________ is used.
a) Centrifugal governor
b) Emergency governor
c) Potter governor
d) None of the mentioned

Answer: b
Clarification: Emergency governor is used in all emergency situations like when the lubrication system is failed, when speed is increased when balancing is disturbed etc.

Steam Turbines for Interviews,

Steam and Gas Turbines Multiple Choice Questions on “Fundamentals of Thermodynamics”.

1. Steam turbines work on __________
a) Otto cycle
b) Dual cycle
c) Rankine cycle
d) None of the mentioned

Answer: c
Clarification: Otto cycle petrol is used as fuel, Rankine cycle is the process followed in steam turbines.

2. Gas turbines work on ___________
a) Rankine cycle
b) Diesel cycle
c) Brayton cycle
d) None of the mentioned

Answer: c
Clarification: Rankine cycle is used in steam turbines. Brayton cycle is followed in gas turbines.

3. Generally, water is used as working fluid in rankine cycle.
a) True
b) False

Answer: a
Clarification: Rankine cycle is followed in steam turbines. In steam turbines generally, water is used as working fluids.

4. Ideal Brayton cycle consists of ________
a) Isoentropic process and Isobaric process
b) Adiabatic process and Isobaric process
c) Adiabatic process
d) None of the mentioned

Answer: a
Clarification: Ideal brayton cycle works on isoentropic process and isobaric process.

5. Actual Brayton cycle works on _________
a) Isoentropic process and Isobaric process
b) Adiabatic process and Isobaric process
c) Isoentropic process
d) None of the mentioned

Answer: b
Clarification: Actual brayton cycle works on Adiabatic process and Isobaric process slight deviations from actual brayton cycle.

6. Brayton cycle is also known as __________
a) Joule cycle
b) Regenerative cycle
c) Carnot cycle
d) None of the mentioned.

Answer: a
Clarification: Regenerative cycle is a closed loop usage of working fluid in rankine cycle. Brayton cycle is also called a joule cycle.

7. Brayton cycle is also called an Ericsson cycle.
a) True
b) False

Answer: a
Clarification: Brayton cycle is also called an ericsson cycle.

8. Brayton cycles are further divided into ______ types.
a) 2
b) 3
c) 4
d) None of the mentioned

Answer: a
Clarification: Brayton cycle is further divided into two types. They are open cycle and closed cycle.

9. Internal combustion chamber is used in _______ Brayton cycle.
a) open
b) closed
c) depends
d) none

Answer: a
Clarification: Internal combustion chambers are present in open cycles to heat the working fluid.

10. Heat exchanger is used in a closed Brayton cycle.
a) True
b) False

Answer: a
Clarification: Heat exchangers are used in closed cycles to raise the temperature of working fluid.

Steam and Gas Turbines Inteview Questions and Answers for freshers on “Nozzle Discharge Coefficients and Calculations”.

1. Coefficient of discharge is the __________ of Actual discharge to the theoretical discharge.
a) ratio
b) product
c) sum
d) none
Answer: a
Clarification: Discharge coefficient is the ratio of actual discharge to the theoretical discharge.

2. Coefficient of discharge is used to measure ___________
a) none of the mentioned
b) pressure exerted by the nozzle on the fluid
c) flow rate allowed by the nozzle
d) resistance offered by the nozzle
Answer: d
Clarification: Coefficient of discharge is used to measure the inaccountable losses of the fluid passing through the nozzle. It is used to measure the resistance exerted by the nozzle.

3. Unit of flow resistance is _________
a) N/m²
b) m²/N
c) KN/Kg
d) No unit
Answer: d
Clarification: Flow resistance is a unit less parameter.

4. Coefficient of discharge is the ____________
a) product of coefficient of velocity and coefficient of contraction
b) arithmetic sum of coefficient of velocity and coefficient of contraction
c) ratio of coefficient of velocity and coefficient of contraction
d) none of the mentioned
Answer: a
Clarification: Cd = Cc*Cv
Where
Cd = Coefficient of discharge
Cc = Coefficient of contraction
Cv = Coefficient of velocity.

5. Coefficient of discharge is _____________
a) directly proportional to coefficient of discharge
b) inversely proportional to square of the coefficient of discharge
c) inversely proportional to coefficient of discharge
d) directly proportional to square of coefficient of discharge
Answer: b
Clarification: Coefficient of resistance is denoted by K and coefficient of discharge is denoted by Cd. Where
K = 1 /Cd².

6. For sharp edge orifice, coefficient of discharge lies between ___________
a) 0.61 – 0.64
b) 0.87 – 0.89
c) 0.50 – 0.61
d) none of the mentioned
Answer: a
Clarification: For sharp edges coefficient of discharge lies between 0.61 – 0.64.

7. Coefficient of discharge (Cd) can be written as Cd=1/K^(0.5).
a) True
b) False
Answer: a
Clarification: Coefficient of discharge is inversely proportional to square root of K.

8. In the equation Cd=1/K^(0.5) what does K mean ?
a) Pressure drop inside the nozzle
b) Mass flow rate
c) Flow resistance
d) None of the mentioned
Answer: c
Clarification: Coefficient of discharge is inversely proportional to square root of flow resistance.

9. Coefficient of discharge is inversely proportional to square root of _______
a) flow resistance
b) pressure drop inside the nozzle
c) none the mentioned
d) flow resistance & pressure drop inside the nozzle
Answer: d
Clarification: Coefficient of discharge can also be written as Cd = m/(density*(pressure drop)*Area)^(0.5) or else Cd = 1/K^(0.5).

10. Coefficient of discharge is directly proportional to mass flow rate.
a) True
b) False
Answer: a
Clarification: When mass flow rate increases coefficient of discharge increases.

Steam and Gas Turbines for interviews,

Steam and Gas Turbines Multiple Choice Questions on “Reaction Blade Profiles”.

1. In reaction turbines steam pressure is used in __________ stages.
a) many
b) one
c) two
d) none
Answer: a
Clarification: In reaction turbines turbine rotates due to the reaction of the flow of fluid.

2. In reaction turbine direction of fluid flow is changed drastically.
a) True
b) False
Answer: b
Clarification: In impulse turbine direction of fluid flow is changed drastically where as in reaction turbine the direction is not turned drastically.

3. Steam velocity graph is same for both reaction and impulse turbines.
a) True
b) False
Answer: a
Clarification: Only steam pressure graph differs and steam velocity graph is same for both impulse and reaction turbine.

4. Reaction turbine blades are _________
a) Plate profile type
b) Aerofoil type
c) Circular profile type
d) None of the mentioned
Answer: b
Clarification: Reaction turbine blades are aerofoil type whereas impulse turbine blades are plate profile type.

5. Reaction turbine blades are _____________
a) symmetrical
b) asymmetrical
c) depends on reaction turbine
d) none of the mentioned
Answer: b
Clarification: Reaction turbine blades are asymmetrical.

6. _____________ is run by the impulse of steam.
a) Reaction turbine
b) Reaction & Impulse turbine
c) Impulse turbine
d) None of the mentioned
Answer: c
Clarification: Impulse turbine is run by the impulse of steam.

7. In reaction turbine nozzle directs the ___________ of steam towards the blades.
a) direction
b) rotation
c) direction & rotation
d) none of the mentioned
Answer: b
Clarification: In impulse turbine nozzle directs the direction of steam and whereas in reaction turbine direction of flow directs the rotation of blades.

8. In reaction turbine direction of fluid flow is maintained by _______
a) Nozzles
b) Rotating blades
c) Guide vanes
d) None of the mentioned
Answer: c
Clarification: In reaction turbines the direction of fluid flow is maintained by guide vanes.

9. In reaction turbines fluid ________ while flowing through the passages.
a) expands
b) contracts
c) depends on the flow
d) none of the mentioned
Answer: a
Clarification: In impulse turbines fluid is totally expanded into nozzle and no expansion takes place while flowing through passage whereas in reaction turbine fluid expands during flowing through passage.

10. Different pressures are maintained on ________ sides of reaction turbine blades.
a) one
b) one
c) many
d) none of the mentioned
Answer: d
Clarification: In reaction turbines two different pressure are maintained on two sides as fluid expands during flow.

Steam and Gas Turbines Multiple Choice Questions on “Automatic Extraction Turbines”.

1. Extraction turbines has an opening in its casing.
a) True
b) False
Answer: a
Clarification: Extraction steam turbines has an opening in its casing.

2. __________ steam is moved to condenser from the turbine in a single step.
a) Total
b) partial
c) depends on load
d) none of the mentioned
Answer: b
Clarification: Some of the steam is extracted at intermediate pressure from casing and the remaining steam is sent to condenser.

3. The steam extraction is __________ extracted.
a) automatically
b) manually
c) automatically or manually
d) none of the mentioned
Answer: c
Clarification: The steam extraction may or may not be automatically extracted.

4. Regulated extraction _________ the total electricity produced.
a) reduces
b) increases
c) has no effect on
d) none of the mentioned
Answer: b
Clarification: Regulated extraction increases the additional electricity produced by steam extraction from casing.

5. Each extracting points on the casing has ______ temperature.
a) different
b) same
c) depends on the load
d) none of the mentioned
Answer: a
Clarification: At each extracting point there will be a different pressure and hence temperature also changes.

6. Each extracting points on the casing has _______ pressure.
a) same
b) different
c) depends on the load
d) none of the mentioned
Answer: b
Clarification: Each extracting point on the casing has a different temperature and pressure.

7. Automatic extraction turbines generate electrical energy.
a) True
b) False
Answer: a
Clarification: Automatic extraction turbines generate both electrical and thermal energy.

8. Automatic extraction turbine generate __________
a) mechanical & thermal energy
b) mechanical energy
c) thermal energy
d) none of the mentioned
Answer: c
Clarification: Automatic extraction turbine generate both electrical and thermal energy.

9. __________ extraction turbines are combined heat and power supply turbines.
a) Automatic
b) Manual
c) Manual or Automatic
d) None of the mentioned
Answer: a
Clarification: Combined heat and power supply turbines are classified as automatic extraction turbines,back pressure turbines and back pressure extraction turbines.

10. In automatic extraction turbines pressure of extracted steam is maintained by __________
a) Extraction points on case
b) Control system
c) Extraction points on case and Control system
d) None of the mentioned
Answer: b
Clarification: In automatic extraction turbines pressure of extracted steam is maintained by control system.