Gas Power Cycles: Master Thermodynamics with Online Quizzes

Question 1

In an Otto cycle, the term 'compression ratio' refers to the ratio of:

Accepted Answer

Cylinder volume at the end of the compression stroke to the cylinder volume at the end of the intake stroke

Answer

Cylinder volume at the end of the intake stroke to the cylinder volume at the end of the compression stroke

Answer

Cylinder pressure at the end of the intake stroke to the cylinder pressure at the end of the compression stroke

Answer

Cylinder pressure at the end of the compression stroke to the cylinder pressure at the end of the intake stroke

Question 2

A regenerator in a gas power cycle serves primarily to:

Accepted Answer

Transfer heat from the exhaust gases to the intake air

Answer

Transfer heat from the intake air to the exhaust gases

Answer

Cool the working fluid in the compressor

Answer

Heat the working fluid in the turbine

Question 3

The purpose of an intercooler in a gas turbine cycle is to:

Accepted Answer

Cool the air between the compressor stages

Answer

Heat the air between the compressor stages

Answer

Cool the exhaust gases before entering the turbine

Answer

Heat the exhaust gases before entering the turbine

Question 4

A potential disadvantage of using a reheat cycle in a gas power plant is:

Accepted Answer

Increased complexity

Answer

Reduced thermal efficiency

Answer

Higher emissions

Answer

Lower maintenance requirements

Question 5

A combined cycle power plant combines a gas turbine cycle with a:

Accepted Answer

Steam turbine cycle

Answer

Rankine cycle

Answer

Brayton cycle

Answer

Otto cycle

Question 6

Which component is essential to the operation of a Brayton cycle?

Accepted Answer

Turbine

Answer

Condenser

Answer

Evaporator

Answer

Expansion valve

Question 7

What is the main purpose of the regenerator in a gas turbine power plant?

Accepted Answer

To preheat air entering the combustor, increasing thermal efficiency.

Answer

To cool exhaust gases exiting the turbine, reducing emissions.

Answer

To generate steam for power generation.

Answer

To condense water vapor in the exhaust gases.

Question 8

In which of the following gas cycle processes does heat transfer occur into the working fluid?

Accepted Answer

Isobaric heat addition

Answer

Adiabatic compression

Answer

Isentropic expansion

Answer

Adiabatic heat rejection

Question 9

What is the primary method for increasing the specific power output of gas turbine engines?

Accepted Answer

Raising the turbine inlet temperature.

Answer

Lowering the compressor pressure ratio.

Answer

Incorporating intercooling between compressor stages.

Answer

Reducing the turbine exhaust temperature.

Question 10

Which of the following is NOT a typical assumption made in the analysis of ideal gas power cycles?

Accepted Answer

The specific heats are temperature-dependent.

Answer

The working fluid behaves as an ideal gas.

Answer

The processes are reversible.

Answer

The combustion is adiabatic.

Question 11

A fundamental distinction between gas turbine engines and reciprocating engines lies in:

Accepted Answer

Gas turbine engines utilize continuous combustion.

Answer

Gas turbine engines operate at higher speeds.

Answer

Reciprocating engines have higher power-to-weight ratios.

Answer

Reciprocating engines are more efficient at higher loads.

Question 12

The mean effective pressure (MEP) of a gas power cycle is a measure of:

Accepted Answer

The average pressure during the expansion stroke

Answer

The average pressure during the compression stroke

Answer

The maximum pressure during the entire cycle

Answer

The minimum pressure during the entire cycle

Question 13

Which of the following factors does NOT influence the thermal efficiency of a gas power cycle?

Accepted Answer

Ambient pressure

Answer

Compression ratio

Answer

Heat addition temperature

Answer

Fuel properties

Question 14

In a Diesel cycle, the fuel is injected:

Accepted Answer

Near the conclusion of the compression stroke

Answer

During constant volume

Answer

During constant pressure

Answer

At the beginning of the expansion stroke

Question 15

Which component in a gas power plant is responsible for converting thermal energy into mechanical energy?

Accepted Answer

Turbine

Answer

Compressor

Answer

Heat exchanger

Answer

Condenser

Question 16

The ratio of the volume at the end of the compression stroke to the volume at the end of the expansion stroke in an Otto cycle is known as the:

Accepted Answer

Compression ratio

Answer

Expansion ratio

Answer

Stroke ratio

Answer

Displacement ratio

Question 17

Which primary distinction exists between a gas turbine and a reciprocating engine?

Accepted Answer

Operating principle

Answer

Fuel type

Answer

Power output

Answer

Efficiency

Question 18

What distinguishes a single-stage gas turbine from a multi-stage gas turbine?

Accepted Answer

Number of turbines

Answer

Number of compressors

Answer

Pressure ratio

Answer

Efficiency

Question 19

Which of the following processes is NOT involved in a gas turbine engine?

Accepted Answer

Condensation

Answer

Compression

Answer

Combustion

Answer

Expansion

Question 20

In an Otto cycle, which process occurs isentropically?

Accepted Answer

Compression stroke

Answer

Intake stroke

Answer

Expansion stroke

Answer

Exhaust stroke

Question 21

What is the ratio of maximum pressure to minimum pressure in an ideal Otto cycle referred to as?

Accepted Answer

Compression ratio

Answer

Expansion ratio

Answer

Cut-off ratio

Answer

Equivalence ratio

Question 22

Which of the following is an advantage of a Diesel cycle compared to an Otto cycle?

Accepted Answer

Higher thermal efficiency due to higher compression ratios

Answer

Lower emissions

Answer

Lower noise levels

Answer

Smaller size

Question 23

What is the primary purpose of intercooling in a gas turbine cycle?

Accepted Answer

Increase the thermal efficiency of the cycle by reducing compressor work

Answer

Reduce the size of the turbine

Answer

Prevent compressor surge

Answer

Reduce the pressure ratio required for the compressor

Question 24

What is the effect of increasing the turbine inlet temperature on the thermal efficiency of a gas turbine cycle?

Accepted Answer

Increases the thermal efficiency due to higher work output

Answer

Does not affect the thermal efficiency

Answer

Decreases the thermal efficiency

Answer

Depends on the compression ratio

Question 25

What is the main function of a regenerator in a gas turbine cycle?

Accepted Answer

Transfer heat from the exhaust gases to the compressed air, improving thermal efficiency

Answer

Cool the turbine blades

Answer

Reduce the pressure drop across the compressor

Question 26

What is the fundamental difference between a gas turbine and a reciprocating engine?

Accepted Answer

Gas turbines operate continuously, while reciprocating engines operate with a reciprocating motion

Answer

Gas turbines are more efficient than reciprocating engines

Answer

Gas turbines are smaller than reciprocating engines

Question 27

In the Otto cycle, during which process does fuel combustion occur?

Accepted Answer

Constant volume heat addition

Answer

Adiabatic expansion

Answer

Constant pressure heat addition

Answer

Adiabatic compression

Question 28

Which gas power cycle is commonly used in modern gas turbine engines?

Accepted Answer

Brayton cycle

Answer

Carnot cycle

Answer

Stirling cycle

Answer

Rankine cycle

Question 29

What is the primary metric used to evaluate the efficiency of a power cycle?

Accepted Answer

Thermal efficiency

Answer

Heat transfer rate

Answer

Work ratio

Answer

Pressure ratio

Question 30

In an open gas power cycle, where does the compressor draw air from?

Accepted Answer

Ambient atmosphere

Answer

Fuel supply

Answer

Combustion chamber

Answer

Heat exchanger

Question 31

What is the primary function of a regenerator in a regenerative gas turbine cycle?

Accepted Answer

Transfers heat from exhaust gases to incoming air

Answer

Cools the turbine blades

Answer

Preheats fuel before combustion

Answer

Acts as an intercooler between compressor stages

Question 32

What is a major drawback of employing intercooling in gas power cycles?

Accepted Answer

Increased power consumption by the compressor

Answer

Reduced emissions

Answer

Lower maintenance costs

Answer

Improved thermal efficiency

Question 33

Which thermodynamic cycle is employed by a typical four-stroke gasoline engine?

Accepted Answer

Otto cycle

Answer

Rankine cycle

Answer

Diesel cycle

Answer

Brayton cycle

Question 34

What key difference distinguishes the Otto and Diesel cycles?

Accepted Answer

The Otto cycle utilizes spark ignition, whereas the Diesel cycle relies on compression ignition.

Answer

Otto cycles exhibit higher efficiency compared to Diesel cycles.

Answer

Diesel cycles operate with a higher compression ratio than Otto cycles.

Question 35

Which thermodynamic cycle is utilized in a gas turbine engine?

Accepted Answer

Brayton cycle

Answer

Otto cycle

Answer

Rankine cycle

Answer

Diesel cycle

Question 36

Which of the following is NOT a factor that influences the efficiency of a gas power cycle?

Accepted Answer

Ambient temperature

Answer

Cut-off ratio

Answer

Specific heat ratio of the working fluid

Answer

Compression ratio

Question 37

The thermal efficiency of a gas power cycle is best defined as:

Accepted Answer

The ratio of work output to heat input.

Answer

The ratio of work output to heat rejected.

Answer

The ratio of heat input to work output.

Answer

The ratio of heat rejected to heat input.

Question 38

In a Diesel engine, increasing the compression ratio typically results in:

Accepted Answer

Enhanced efficiency and higher peak pressure.

Answer

Reduced efficiency and higher peak pressure.

Answer

Enhanced efficiency and lower peak pressure.

Answer

Reduced efficiency and lower peak pressure.

Question 39

Which of the following is a potential advantage of the Brayton cycle compared to the Otto cycle?

Accepted Answer

Higher operating temperatures.

Answer

Enhanced thermal efficiency.

Answer

Lower operating temperatures.

Answer

Reduced emissions.

Question 40

The purpose of a reheat cycle in a gas turbine engine is to:

Accepted Answer

Elevate the overall cycle efficiency by adding heat to the working fluid after partial expansion.

Answer

Enhance the engine's power output by increasing the air supply to the combustion chamber.

Answer

Lower the peak temperature within the turbine.

Question 41

In a gas turbine engine, the implementation of a regenerator aims to:

Accepted Answer

Improve efficiency by preheating the incoming air utilizing the heat from the exhaust gases.

Answer

Minimize the size of the engine.

Answer

Augment the power output of the engine.

Question 42

In a gas power cycle, the work performed by the system during the expansion process is graphically represented by:

Accepted Answer

The area enclosed by the expansion process on the pressure-volume diagram.

Answer

The area enclosed by the compression process on the pressure-volume diagram.

Answer

The difference in enthalpy between the turbine's inlet and outlet.