Category: Steam and Gas Turbines Objective Questions

Steam and Gas Turbines Questions for entrance exams on “Requirements for Radial Equilibrium and Velocity Diagrams”.

1. For radial equilibrium axial flow is assumed.
a) True
b) False
Answer: b
Clarification: For radial equilibrium asymmetrical flow is assumed.

2. For radial equilibrium constant velocity is assumed.
a) True
b) False
Answer: a
Clarification: For radial equilibrium meridional velocity is assumed to be constant.

3. For simple radial equilibrium it is assumed that ______________
a) r*Vu = constant
b) r/Vu = constant
c) Vu/r = constant
d) None of the mentioned
Answer: a
Clarification: For a free vortex in a radial equilibrium it is assumed that the product of radius and velocity has remained as constant.

4. Secondary losses are caused due to _________
a) frictional forces
b) lift force induced in turbine
c) drag force induced by secondary force
d) none of the mentioned
Answer: c
Clarification: Secondary losses are caused due to drag forces induced by secondary forces.

5. For radial equilibrium it is assumed that viscosity is __________
a) high
b) negligible
c) low
d) none of the mentioned
Answer: b
Clarification: For radial equilibrium the flow is assumed to be asymmetrical and viscous forces are assumed to be negligible.

6. In radial equilibrium method blade force is assumed to be ____________
a) high
b) low
c) zero
d) none
Answer: c
Clarification: Blade forces are assumed to be zero in radial equilibrium.

7. For radial equilibrium it is assumed that heat transfer is ____________
a) zero
b) high
c) low
d) none
Answer: a
Clarification: For radial equilibrium it is assumed that the flow is non viscous flow and heat transfer is zero.

8. For radial equilibrium entropy term is _________
a) high
b) low
c) neglected
d) none of the mentioned
Answer: c
Clarification: For radial equilibrium method entropy term is neglected.

9. For radial equilibrium it is assumed that the steam lines are ___________ to the axis line.
a) perpendicular
b) parallel
c) inclined
d) none of the mentioned
Answer: b
Clarification: For radial equilibrium it is assumed that the steam lines are axis parallel and have no inclination.

10. For radial equilibrium friction is neglected.
a) True
b) False
Answer: a
Clarification: Friction is neglected in radial equilibrium.

Steam and Gas Turbines for entrance exams,

Steam and Gas Turbines Multiple Choice Questions on “Flow Passages with Radial Equilibrium”.

1. Flow through turbo machinery is ________
a) one dimensional
b) two dimensional
c) three dimensional
d) none of the mentioned
Answer: c
Clarification: Fluid flow in turbo machinery is a three dimensional flow.

2. Third direction of the flow in turbo machinery is _______
a) blade width
b) blade height
c) heat flow direction
d) none of the mentioned
Answer: b
Clarification: Flow direction and tangential flow direction are the two directions and the third direction is blade height.

3. Centrifugal forces acts in ________
a) tangential direction
b) flow direction
c) radial direction
d) none of the mentioned
Answer: c
Clarification: Centrifugal flow acts in the third direction that is radial direction.

4. The field produced by centrifugal force distorts the flow velocity.
a) True
b) False
Answer: a
Clarification: Centrifugal force produced creates a field on the flow and distorts the velocity of flow.

5. Radial equilibrium theory assumes that flow is in equilibrium before and after the fluid entering the blade.
a) True
b) False
Answer: a
Clarification: Radial equilibrium method assumes flow is in equilibrium before the fluid enters and after the fluid leaving the blade.

6. Radial equilibrium theory is more important for Radial flow machines.
a) True
b) False
Answer: b
Clarification: Radial equilibrium theory is more important for axial flow machines.

7. In radial equilibrium method centrifugal force is equated to __________
a) pressure force
b) axial force
c) centripetal force
d) none of the mentioned
Answer: a
Clarification: For a particle to move in constant radius centrifugal force must be equal to pressure force.

8. For radial equilibrium flow radial component must be _______ along the radial direction of flow.
a) higher
b) zero
c) lesser
d) none of the mentioned
Answer: b
Clarification: In radial equilibrium method radial component must be equal to zero.

9. Stagnation enthalpy is _______ in turbo machine along the radial direction.
a) higher
b) zero
c) constant
d) none of the mentioned
Answer: c
Clarification: Stagnation enthalpy is constant in turbo machines along the radial flow direction.

10. Stagnation enthalpy is _________ at intake and discharge.
a) constant
b) low
c) high
d) none of the mentioned
Answer: a
Clarification: Stagnation enthalpy is constant in turbo machines along the radial flow direction at intake and discharge.

Steam and Gas Turbines Multiple Choice Questions on “Centrifugal Compressor”.

1. Centrifugal compressors are also known as ____________
a) turbo compressors
b) radial compressors
c) turbo & radial compressors
d) none of the mentioned
Answer: b
Clarification: Centrifugal compressors sometimes called as radial compressors.

2. In idealized turbo machinery, pressure rise is done by adding _______
a) Temperature
b) Mass
c) Kinetic energy
d) None of the mentioned
Answer: c
Clarification: In idealized turbo machinery the pressure rise is done by adding kinetic energy.

3. The pressure rise in impeller is _________ the rise in diffuser.
a) equal to
b) greater than
c) equal to or greater than
d) none of the mentioned
Answer: d
Clarification: Not in all cases pressure rise in diffuser equals to pressure rise in impeller in some cases pressure rise in impeller will be more than that of diffuser.

4. In centrifugal compressor velocity of flow leaving the impeller is equals to _______ in many cases.
a) Speed of sound
b) Double the speed of sound
c) Triple the speed of sound
d) None of the mentioned
Answer: a
Clarification: Initially the flow enters straightly into the impeller and the impeller pushes the flow inwards to spin faster and finally when the flow is leaving impeller it has almost speed of sound.

5. ________ are used as stationary compressors in steam turbines.
a) Moving vanes
b) Guide vanes
c) Moving & Guide vanes
d) None of the mentioned
Answer: b
Clarification: Guide vanes are used as stationary compressors where guide vanes reduce the velocity and according to Bernoulli’s theorem when velocity is reduced its pressure is increased.

6. ________________ has large change in inlet to exit radius when compared to centrifugal compressors.
a) Axial compressors
b) Axial & Centrifugal compressors
c) Centrifugal compressors
d) None of the mentioned
Answer: c
Clarification: Centrifugal compressors has large change in inlet to exit temperature when compared to axial compressor.

7. The first part in both centrifugal compressor and axial compressor are similar.
a) True
b) False
Answer: a
Clarification: The first in both centrifugal compressor and axial compressor are similar.

8. Centrifugal compressor __________ the energy by increasing the radius where as centrifugal fan decreases the energy.
a) increases
b) decreases
c) both follow the same
d) none of the mentioned
Answer: b
Clarification: Both centrifugal compressor and centrifugal fan are similar as both increases the energy by reducing the radius.

9. Centrifugal compressors increases the density of fluid more than ________
a) 1%
b) 3%
c) 5%
d) 7%
Answer: c
Clarification: Centrifugal compressors increases the density of fluid more than 5 %.

10. Centrifugal fan has relative fluid velocities ______
a) Mach number more than 0.3
b) Mach number less than 0.1
c) Mach number less than 0.3
d) Mach number more than 0.5
Answer: c
Clarification: Centrifugal fans often operate at fluid velocities less than mach number 0.3.

Steam and Gas Turbines Multiple Choice Questions on “The Regenerator”.

1. In regenerator energy is stored in ___________
a) gas medium
b) fluid medium
c) thermal medium
d) none of the mentioned
Answer: b
Clarification: In regenerator energy is stored in the thermal medium.

2. Both hot and cold fluid used in regenerators is __________
a) same fluid
b) different fluid
c) depending on the situation
d) none of the mentioned
Answer:a
Clarification: Both hot and cold fluid used in regenerators is the same fluid.

3. Heat regenerators are ___________
a) dependent
b) repetitive
c) costant
d) none of the mentioned
Answer: c
Clarification: Heat regenerators are repetitive.

4. Rotatary regenerators are _________ flow path.
a) parallel
b) counter flow path
c) repetitive
d) none of the mentioned
Answer: b
Clarification: Rotatry regenerators have counter flow path.

5. In a fixed matrix regenerator flow is __________
a) reversible
b) irreversible
c) repetitive
d) none of the mentioned
Answer: a
Clarification: In a fixed matrix regenerator flow is reversible. In fixed matrix regenerator flow can be in both directions depending on the requirement.

6. In a fixed flow regenerator flow is __________
a) repetitive
b) counter
c) parallel
d) none of the mentioned
Answer: c
Clarification: In a fixed flow regenerator flow is counter current.

7. Fixed matrix regenerator is a part of ________ system.
a) valveless
b) valve
c) depending on the requirement
d) none of the mentioned
Answer: a
Clarification: Fixed matrix regenerators is a part of valveless system. In fixed matrix flow is reversible.

8. Rothemuhle regenerator has same design of _________ regenerator.
a) fixed matrix
b) varying matrix
c) varying & fixed matrix
d) none of the mentioned
Answer: a
Clarification: Rothemuhle regenerator has same design of fixed matrix regenerator.

9. Regenerators used in cryogenics are ________
a) small
b) large
c) medium
d) none of the mentioned
Answer: b
Clarification: Regenerators used in cryogenics are large. Cryogenic engines require large structures.

10. Regenerators have lower surface area than recuperator.
a) True
b) False
Answer: b
Clarification: Regenerators have higher surface area than recuperators.

Steam and Gas Turbines Multiple Choice Questions on “Bearing System in Gas Turbines”.

1. Journal bearings are used to give ______ support.
a) radial
b) axial
c) radial & axial
d) none of the mentioned
Answer: a
Clarification: Radial support is given by using journal bearing. Axis of the bearings keeps on changing with the rotation.

2. _________ positioning is given by thrust bearings.
a) Axial
b) Radial & axial
c) Radial
d) None of the mentioned
Answer: c
Clarification: Thrust bearings is used to give axial positioning. Thrust bearings provide supporting reaction to the bearings in axial direction.

3. ________ bearings are used in aircraft engines.
a) Roller
b) Axial
c) Radial
d) All of the mentioned
Answer: d
Clarification: Roller bearings are used in aircraft engines. Each bearing is used in its respective place where its presence is required.

4. Ball bearings are used in aircraft engines.
a) True
b) False
Answer: a
Clarification: Ball bearings are used in aircraft engines.

5. ____________ bearings are used in all industrial turbines.
a) Roller
b) Ball
c) Journal
d) None of the mentioned
Answer: c
Clarification: Journal bearings are used in all industrial turbines. Roller and Ball bearings are used in air craft engines.

6. Journal bearings are _________ sized.
a) square
b) round
c) large
d) none of the mentioned
Answer: b
Clarification: Journal bearings can be either split or round sized. No bearing is present in square sized and all bearings are small in size.

7. Journal bearings can be ________ sized.
a) round
b) split
c) round & split
d) none of the mentioned
Answer: c
Clarification: Journal bearings can be split or round sized. The selection of size either round or split is selected based on the forces acting and the use of the bearing at that respective place.

8. Precision insert type bearings have _______ lining.
a) thin
b) thick
c) small
d) none of the mentioned
Answer: a
Clarification: Precision insert type bearings have thin lining and are used in the internal combustion engine.

9. Sleeve bearings are commonly _________ type.
a) split
b) round
c) journal
d) none of the mentioned
Answer: a
Clarification: Sleeve bearings are commonly split type. Sleeve bearings are used in sleeves and split type is required in that place.

10. Cylindrical _______ bearing has split design.
a) roller
b) bore
c) journal
d) none of the mentioned
Answer: b
Clarification: Cylindrical bore bearing has split design. Round bearings increase the point of contact and increases the energy losses.

Automobile Engineering Multiple Choice Questions on “Nonconventional Engines”.

1. What is a dual fuel engine?
a) The engine which uses gaseous and liquid fuel
b) The engine which uses two liquid fuels
c) The engine which uses two gaseous fuels
d) The engine which uses one liquid and any other fuel
Answer: a
Clarification: The duel fuel engine uses gaseous and liquid fuel. The dual-fuel engine works on the diesel cycle. The gaseous fuel is called the primary fuel. The mixture of air and gaseous fuel is compressed in the cylinder.

2. Which of the following has the same combustion as HCCI (Homogeneous Charge Compression Ignition) engine?
a) SI engine
b) CI engine
c) Hybrid of both SI and CI engine
d) Wankel engine
Answer: c
Clarification: HCCI engine has the same combustion as a hybrid of both SI and CI engine. HCCI is a form of IC engine in which well-mixed fuel and air are compressed to the auto-ignition temperature of the fuel.

3. Which of the following is true for the HCCI engine?
a) Emits high NO_x and soot
b) Have a large power range
c) Efficiency is comparatively less
d) Pre-catalyst hydrocarbon emissions are higher
Answer: d
Clarification: Pre-catalyst hydrocarbon emissions are higher is one of the disadvantages of the HCCI engine. The advantages of the HCCI engine are NO_x and soot emissions are almost negligible.

4. For which of the following engine lean-burn concept is ideal?
a) CI engine
b) SI engine
c) Free piston engine
d) Wankel engine
Answer: b
Clarification: SI engines are more ideal for the lean-burn concept. A lean-burn mode is a way to reduce throttling losses. In SI engine, the power is reduced by partially closing a throttle.

5. By which technique can the charge stratification be achieved?
a) Injection
b) Carburetion
c) Lean burn technology
d) Injection as well as carburation
Answer: d
Clarification: The charge stratification can be achieved by injection as well as carburation. Charge stratification means providing different fuel-air mixture strengths at various places in the combustion chamber.

6. Which of the following is true for stratified charge engine?
a) More prone for knock
b) Multi-fuel capabilities
c) More throttling losses
d) Overall rich mixture
Answer: b
Clarification: Multi-fuel capabilities are one of the advantages of the stratified charge engine. The stratified engines are developed to combine both advantages of diesel and petrol engines.

7. What is true about the Wankel engine?
a) It is a rotary external combustion engine
b) It is more expensive
c) It has a longer operating cycle
d) It has less time to complete the combustion
Answer: c
Clarification: Wankel engine is a type of internal combustion engine using rotary design to convert pressure into a rotating motion. It does not make use of reciprocating pistons.

8. Where is the variable compression ratio used?
a) SI engine
b) CI engine
c) Wankel engine
d) HCCI engine
Answer: a
Clarification: Variable compression is used in SI engines. There are several methods for changing both the geometric and effective compression ratio.

9. Which of the following is true for stratified charge engine?
a) More prone for knock
b) It uses an overall rich mixture
c) It has a lot of throttling losses
d) It has multi-fuel capabilities
Answer: d
Clarification: Stratified charge engine has multi-fuel capabilities. The advantages of a stratified charge engine are higher thermodynamic efficiency and reduced air pollution.

10. Which of the following is true about the Stirling engine?
a) High efficiency
b) Quiet operation
c) Compatible with alternative and renewable energy
d) High efficiency, quiet operation and compatible with renewable energy
Answer: d
Clarification: The Stirling engine has high efficiency. A Stirling engine is a heat engine operating on cyclic compression and expansion of air or any other fluid.