Turbomachinery: A Comprehensive Guide for Mechanical Engineering Students

Question 1

Which of the following is not considered a type of turbomachinery commonly used in fluid mechanics?

Accepted Answer

Electric motors

Answer

Pumps

Answer

Compressors

Answer

Turbines

Question 2

What is the primary purpose of a centrifugal pump in a fluid system?

Accepted Answer

To increase the pressure of the fluid

Answer

To decrease the pressure of the fluid

Answer

To mix different fluids together

Answer

To separate different fluids

Question 3

What is the primary function of a diffuser in a centrifugal compressor?

Accepted Answer

To reduce the velocity of the fluid, thereby increasing its pressure

Answer

To increase the velocity of the fluid, thereby decreasing its pressure

Answer

To alter the direction of the fluid flow

Answer

To facilitate the mixing of different fluids

Question 4

What is the key difference between a subsonic and a supersonic fan?

Accepted Answer

Subsonic fans operate below the speed of sound, while supersonic fans operate above the speed of sound

Answer

Supersonic fans operate below the speed of sound, while subsonic fans operate above the speed of sound

Answer

Subsonic fans have a lower pressure ratio than supersonic fans

Answer

Supersonic fans have a lower pressure ratio than subsonic fans

Question 5

Which of the following characteristics is typically associated with an axial pump?

Accepted Answer

Suitable for high-flow applications

Answer

High pressure ratio

Answer

Superior efficiency compared to centrifugal pumps

Answer

Suitable for pumping high-viscosity liquids

Question 6

What is the main purpose of a volute in a centrifugal pump?

Accepted Answer

To convert kinetic energy of the fluid into pressure energy

Answer

To increase the velocity of the fluid

Answer

To change the direction of the fluid flow

Answer

To decrease the pressure of the fluid

Question 7

Which of the following is a type of axial turbine?

Accepted Answer

Kaplan turbine

Answer

Pelton turbine

Answer

Francis turbine

Answer

Impulse turbine

Question 8

Which of the following is NOT a type of turbomachinery?

Accepted Answer

Electric motor

Answer

Pump

Answer

Turbine

Answer

Compressor

Question 9

What is the primary function of a centrifugal pump?

Accepted Answer

To increase pressure and flow rate

Answer

To convert mechanical energy into kinetic energy

Answer

To convert kinetic energy into pressure energy

Answer

To remove impurities from fluids

Question 10

Which of the following is a key design parameter for axial turbines?

Accepted Answer

Blade angle and flow rate

Answer

Head and speed

Answer

Material properties

Answer

Inlet pressure

Question 11

What is the purpose of a diffuser in a compressor?

Accepted Answer

To decrease velocity and increase pressure

Answer

To increase pressure

Answer

To remove impurities

Answer

To convert potential energy to kinetic energy

Question 12

What is the relationship between the pressure head and the flow rate in a centrifugal pump?

Accepted Answer

Directly proportional

Answer

Inversely proportional

Answer

Quadratic

Answer

Exponential

Question 13

Why is efficiency a critical factor in turbomachinery design and operation?

Accepted Answer

To reduce energy consumption and lower operating costs

Answer

To increase output power without regard to energy consumption

Answer

To minimize manufacturing and maintenance expenses

Question 14

Which of the following accurately describes the environmental impact of turbomachinery operations?

Accepted Answer

Turbomachinery operations can have significant environmental impacts due to noise pollution, emissions, and energy consumption.

Answer

Turbomachinery operations are environmentally friendly due to their energy efficiency.

Answer

Noise pollution is the primary environmental concern, with emissions being a minor factor.

Answer

Energy efficiency is not a significant consideration in the environmental impact of turbomachinery.

Question 15

Identify the type of turbomachine that is NOT a reciprocating engine.

Accepted Answer

Reciprocating engine

Answer

Centrifugal pump

Answer

Axial compressor

Answer

Wind turbine

Question 16

What is the main purpose of a centrifugal pump?

Accepted Answer

Increase fluid pressure

Answer

Convert rotational energy to linear energy

Answer

Remove impurities from fluids

Answer

Generate electricity

Question 17

What is the purpose of the diffuser in a centrifugal compressor?

Accepted Answer

Convert kinetic energy to pressure energy

Answer

Increase flow rate

Answer

Reduce turbulence

Answer

Protect compressor blades

Question 18

Which characteristic is unique to positive displacement fans?

Accepted Answer

Constant flow rate regardless of pressure

Answer

Low efficiency

Answer

High noise levels

Answer

Suitable for high-pressure applications

Question 19

Distinguish between a pump and a turbine based on their energy conversion capabilities.

Accepted Answer

Pumps convert mechanical energy to fluid energy, while turbines convert fluid energy to mechanical energy

Answer

Turbines convert mechanical energy to fluid energy, while pumps convert fluid energy to mechanical energy

Answer

Pumps and turbines perform the same function in opposite directions

Answer

There is no difference between a pump and a turbine

Question 20

What is the impact of increasing the rotational speed of a centrifugal pump?

Accepted Answer

Increased flow rate and pressure

Answer

Decreased flow rate and pressure

Answer

Increased flow rate but decreased pressure

Answer

Decreased flow rate but increased pressure

Question 21

What is the primary advantage of employing a variable-geometry turbine?

Accepted Answer

Enhanced efficiency across a wide range of operating conditions

Answer

Reduced production costs

Answer

Increased power generation

Answer

Extended lifespan

Question 22

In selecting the most suitable turbomachinery for a specific application, which factors are of primary importance for engineers to consider?

Accepted Answer

Flow rate, pressure increase requirements, and energy efficiency

Answer

Size, weight, and initial cost

Answer

Material properties and manufacturing processes

Answer

Environmental regulations and industry safety standards

Question 23

Turbomachinery finds extensive applications in various industries. Which of the following options accurately describes these applications?

Accepted Answer

Power plants, propulsion systems, and fluid management

Answer

Power generation only

Answer

Aircraft engines solely

Answer

Liquid pumping only

Question 24

How do the material properties of turbomachinery components affect their performance and durability?

Accepted Answer

High strength and stiffness materials enhance efficiency and reduce vibration.

Accepted Answer

Low density materials reduce inertia and improve responsiveness.

Accepted Answer

High thermal conductivity materials improve heat dissipation and prevent overheating.

Question 25

What is the main purpose of a turbine in a turbomachine system?

Accepted Answer

To convert kinetic energy of a fluid into mechanical energy

Answer

To convert mechanical energy into kinetic energy of a fluid

Answer

To generate an electrical current

Answer

To regulate fluid flow

Question 26

Which type of compressor is typically used in applications requiring high mass flow rates, such as in aircraft engines?

Accepted Answer

Axial compressor

Answer

Centrifugal compressor

Answer

Reciprocating compressor

Answer

Scroll compressor

Question 27

What is the primary function of a fan?

Accepted Answer

To move air

Answer

To generate thrust

Answer

To compress air

Answer

To measure fluid flow

Question 28

What is the main purpose of a diffuser in a turbomachine?

Accepted Answer

To decrease fluid velocity and increase fluid pressure

Answer

To increase fluid velocity and decrease fluid pressure

Answer

To change the direction of fluid flow

Answer

To measure fluid flow

Question 29

Which component is NOT part of a gas turbine engine?

Accepted Answer

Condenser

Answer

Compressor

Answer

Combustor

Answer

Turbine

Question 30

Which of the following is not a major category of turbomachinery?

Accepted Answer

Transformer

Answer

Pump

Answer

Turbine

Answer

Compressor

Question 31

What is the function of a diffuser in a centrifugal compressor?

Accepted Answer

To convert kinetic energy to pressure energy

Answer

To reduce fluid temperature

Answer

To increase fluid velocity

Answer

To separate gas and liquid phases

Question 32

What is the fundamental difference between radial and axial turbomachines?

Accepted Answer

Flow direction relative to the axis of rotation

Answer

Number of stages

Answer

Pressure ratio

Answer

Efficiency

Question 33

What is the specific function of a volute casing in a centrifugal pump?

Accepted Answer

To collect and redirect fluid from the impeller

Answer

To reduce pressure pulsations

Answer

To increase flow rate

Answer

To improve efficiency

Question 34

Which type of turbomachine employs the principle of dynamic lift to generate thrust?

Accepted Answer

Propeller

Answer

Compressor

Answer

Fan

Answer

Turbine

Question 35

What is the significance of specific speed in turbomachinery design?

Accepted Answer

It helps determine the optimal operating conditions

Answer

It serves as an indicator of machine efficiency

Answer

It defines the physical dimensions of the machine

Answer

It has no practical value in design

Question 36

How does scale influence the design and performance of turbomachinery? Analyze the challenges and opportunities presented by scaling up or down.

Accepted Answer

Scaling up or down necessitates meticulous redesign to preserve optimal performance.

Answer

Scaling up always enhances efficiency due to reduced viscous effects.

Answer

Scaling down always diminishes performance due to increased viscous effects.

Answer

Scale has no significant impact on turbomachinery design or performance.

Question 37

Which of the following is the primary function of a centrifugal pump?

Accepted Answer

To convert mechanical energy into kinetic energy of a fluid

Answer

To reduce the pressure of a fluid

Answer

To increase the temperature of a fluid

Question 38

What is the key distinction between an axial pump and a centrifugal pump?

Accepted Answer

The direction of fluid flow relative to the impeller

Answer

The size and capacity of the pump

Answer

The type of fluid being pumped

Question 39

Which component plays a vital role in a gas turbine engine?

Accepted Answer

Compressor

Answer

Impeller

Answer

Volute

Answer

Diffuser

Question 40

What is the intended purpose of the stator blades in a turbomachine?

Accepted Answer

To guide and redirect the fluid flow

Answer

To convert kinetic energy into mechanical energy

Answer

To increase the pressure of the fluid

Answer

To lubricate the moving parts

Question 41

Which type of efficiency measure is commonly used in the context of turbomachinery?

Accepted Answer

Isentropic efficiency

Answer

Mechanical efficiency

Answer

Volumetric efficiency

Question 42

What is the expected outcome of increasing the blade speed in a centrifugal compressor?

Accepted Answer

Increased pressure rise

Answer

Reduced efficiency

Answer

No change in performance

Answer

Increased mass flow rate

Question 43

Which factors primarily affect the specific speed of a pump?

Accepted Answer

Fluid density and impeller diameter

Answer

Pump speed and discharge pressure

Answer

Suction head and discharge head

Answer

Inlet and outlet pipe diameters

Question 44

What is the primary advantage of a multistage axial compressor compared to a single-stage compressor?

Accepted Answer

Higher pressure ratio with reduced blade loading

Answer

Lower manufacturing cost

Answer

Reduced size and weight

Answer

Improved efficiency at high pressure ratios

Question 45

Which type of fan is characterized by its radial blades and ability to generate high pressure rise?

Accepted Answer

Centrifugal fan

Answer

Cross-flow fan

Answer

Mixed-flow fan

Answer

Axial fan

Question 46

In a centrifugal pump, the pressure rise is primarily attributed to:

Accepted Answer

Centrifugal force generated by the impeller

Answer

Viscosity of the fluid

Answer

Pressure difference between the inlet and outlet

Answer

Force of gravity

Question 47

The efficiency of a turbine is primarily determined by:

Accepted Answer

Blade efficiency, which reflects losses due to flow deviation and friction, and hydraulic losses due to leakage and turbulence

Answer

Pressure ratio, which affects the amount of energy extracted

Answer

Number of blades, which influences flow distribution but not overall efficiency

Answer

Rotational speed, which impacts power output but not efficiency

Question 48

The stall margin of a compressor represents:

Accepted Answer

The range of flow rates at which the compressor can operate without experiencing flow separation and efficiency loss

Answer

The maximum pressure ratio that the compressor can achieve

Answer

The efficiency at which the compressor operates under optimal conditions

Question 49

A major design consideration for a fan is:

Accepted Answer

Noise generation, as fans operate at relatively high speeds and can produce significant acoustic emissions

Answer

Specific speed, which is more relevant for pumps and turbines

Answer

Isentropic efficiency, which is important but not the primary design focus for fans

Answer

Rotor blade angle, which affects airflow but is typically optimized for a specific operating range

Question 50

The efficiency of a turbomachine is typically quantified using the:

Accepted Answer

Isentropic efficiency, which compares the actual work done to the theoretical work assuming an isentropic process

Answer

Volumetric efficiency, which is specific to positive displacement machines

Answer

Thermal efficiency, which is more relevant for heat engines

Answer

Mechanical efficiency, which measures losses due to friction and other mechanical components

Question 51

The specific speed of a turbomachine is a dimensionless parameter that:

Accepted Answer

Relates the machine's size, speed, and flow rate, providing insights into its design and operating characteristics

Answer

Indicates the efficiency of the machine

Answer

Determines the pressure ratio that the machine can achieve

Answer

Is independent of the machine's design

Question 52

A key benefit of using turbomachinery in industrial applications is:

Accepted Answer

High power density, allowing for compact and efficient power generation or fluid movement

Answer

Low maintenance, which is not a primary advantage of turbomachinery

Answer

Long service life, which can be achieved with proper design and maintenance

Answer

Low noise, which is not typically a major consideration for industrial applications