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A gas turbine engine operates on a thermodynamic cycle where air is compressed, fuel is added and ignited, and the resulting hot gases expand through a turbine to produce power.
Answer: True
The fundamental operational principle of a gas turbine engine involves a thermodynamic cycle where air is compressed, fuel is introduced and combusted, and the resultant hot gases expand through a turbine to generate power.
The primary components of a gas turbine engine, in order of airflow, are the turbine, combustor, and compressor.
Answer: False
The correct sequence of primary components in the direction of airflow through a gas turbine engine is the compressor, followed by the combustor, and finally the turbine.
In the Brayton cycle, energy is added through combustion at a constant volume, and the air is reused within a closed system.
Answer: False
The ideal Brayton cycle describes energy addition through combustion at constant pressure, not constant volume. Furthermore, it is an open cycle, meaning the working fluid (air) is not reused within a closed loop.
The gas generator core of a gas turbine includes the compressor, combustor, and a turbine solely for driving external equipment.
Answer: False
The gas generator core of a gas turbine comprises the compressor, combustor, and a turbine specifically designed to drive the compressor. A separate power turbine is responsible for driving external equipment.
Air is ducted around the combustor primarily to mix with fuel and ensure complete combustion.
Answer: False
A substantial portion of the air compressed by the compressor is ducted around the primary combustion zone primarily to cool the combustor liner and turbine components, thereby preventing thermal damage.
What thermodynamic cycle is typically the basis for a gas turbine engine's operation?
Answer: Brayton cycle
Gas turbine engines fundamentally operate based on the Brayton thermodynamic cycle, which involves processes of compression, heat addition (combustion), expansion, and heat rejection.
Which of the following is listed as a fundamental core component of all gas turbine engines?
Answer: Combustor
The combustor, where fuel is mixed with compressed air and ignited, is a fundamental core component present in all gas turbine engines, alongside the compressor and turbine.
According to the ideal Brayton cycle description, how is energy added to the system?
Answer: At constant pressure
In the ideal Brayton cycle, energy is added to the working fluid through combustion at a constant pressure process.
What is the 'gas generator' or core of a gas turbine responsible for?
Answer: Generating the high-temperature, high-pressure gas.
The gas generator, or core, of a gas turbine is responsible for producing the high-temperature, high-pressure gas stream necessary for operation, comprising the compressor, combustor, and gas generator turbine.
What is the primary purpose of the air that is ducted around the combustor in a gas turbine?
Answer: To cool the combustor and turbine components
A significant portion of the air from the compressor is ducted around the primary combustion zone to provide cooling for the combustor liner and the subsequent turbine stages, protecting them from extreme temperatures.
John Barber patented the first true gas turbine in 1791, intending it for use in powering a horseless carriage.
Answer: True
Historical records indicate that John Barber received a patent in 1791 for what is considered the first true gas turbine, conceptualized for the purpose of powering a horseless carriage.
Ægidius Elling's 1903 gas turbine was the first to generate more power than required to operate itself, producing approximately 11 horsepower.
Answer: True
In 1903, Ægidius Elling developed a gas turbine that achieved a significant milestone by producing net power, generating approximately 11 horsepower, thereby exceeding the power needed for its own operation.
Frank Whittle patented his jet propulsion gas turbine design in 1937, with the first successful test run occurring in 1930.
Answer: False
Frank Whittle patented his jet propulsion gas turbine design in 1930; however, the first successful test run of his engine did not occur until 1937.
The Junkers Jumo 004 engine, entering production in 1944, was significant for powering the first German military jets.
Answer: True
The Junkers Jumo 004 engine, which entered full production in 1944, played a pivotal role in powering the initial generation of German military jet aircraft, marking a significant advancement in aviation technology.
The Rover JET1, unveiled in 1950, was the first car powered by a gas turbine engine, but it was deemed practical for mass production.
Answer: False
While the Rover JET1, introduced in 1950, was indeed the first automobile powered by a gas turbine engine, it was ultimately considered impractical for mass production due to various operational challenges.
The Royal Navy's motor gunboat MGB 2009, converted in 1947, was among the early marine applications of gas turbines.
Answer: True
The conversion of the Royal Navy's motor gunboat MGB 2009 in 1947 represents a significant early instance of gas turbine application in marine propulsion.
The first operational Holzwarth gas turbine in 1910 achieved high efficiency but had a low power output.
Answer: False
The first operational Holzwarth gas turbine, developed in 1910 and utilizing pulse combustion, produced an output of 150 kW (200 hp) but did not achieve high thermal efficiency compared to contemporary reciprocating engines.
Who patented the first true gas turbine, and what was its intended application?
Answer: John Barber, for a horseless carriage
John Barber is credited with patenting the first true gas turbine in 1791, with the design intended for use in powering a horseless carriage.
What significant milestone did Ægidius Elling achieve with his gas turbine in 1903?
Answer: It produced more power than it consumed to operate.
In 1903, Ægidius Elling constructed the first gas turbine capable of generating net power, meaning it produced more power than was required for its own operation.
When did Frank Whittle's design for a gas turbine for jet propulsion receive its patent?
Answer: 1930
Frank Whittle secured the patent for his groundbreaking gas turbine design intended for jet propulsion in the year 1930.
What was the historical significance of the Junkers Jumo 004 engine entering full production in 1944?
Answer: It marked the beginning of widespread use of turbines for aircraft propulsion.
The full production of the Junkers Jumo 004 engine in 1944 signified a pivotal moment, enabling the deployment of the first German military jets and heralding the era of widespread gas turbine application in aviation.
What was the Rover JET1 notable for?
Answer: Being the first car powered by a gas turbine engine.
The Rover JET1, unveiled in 1950, holds the distinction of being the first automobile powered by a gas turbine engine.
Which of the following was among the first ships designed specifically for gas turbine propulsion?
Answer: Bold class fast patrol boats
The Bold class fast patrol boats, constructed in 1953, were the first vessels specifically designed from the outset for gas turbine propulsion.
What was a key characteristic of the first operational Holzwarth gas turbine in 1910?
Answer: It used pulse combustion.
The first operational Holzwarth gas turbine, developed in 1910, was characterized by its use of pulse combustion technology.
A turboprop engine's primary function is to generate thrust directly from its exhaust gases, similar to a turbojet.
Answer: False
The primary function of a turboprop engine is to drive an aircraft propeller. While it does have a turbine and exhaust, its main thrust contribution comes from the propeller, unlike a turbojet which relies predominantly on exhaust thrust.
Turbofan engines improve fuel efficiency and reduce noise compared to turbojets by utilizing a ducted fan to move additional air.
Answer: True
Turbofan engines enhance fuel efficiency and reduce noise levels relative to turbojets by incorporating a large ducted fan that moves a significant volume of bypass air around the core engine.
Aeroderivative gas turbines are heavier and slower to respond than traditional industrial gas turbines.
Answer: False
Aeroderivative gas turbines, derived from aircraft engine designs, are typically lighter and exhibit faster response times compared to traditional industrial gas turbines.
Microturbines typically range from 25 to 500 kilowatts and can achieve up to 85% efficiency in cogeneration applications.
Answer: True
Microturbines are characterized by their relatively small size, typically ranging from 25 to 500 kilowatts, and can achieve high overall efficiencies, up to 85%, when integrated into combined heat and power (cogeneration) systems.
An externally fired gas turbine (EFGT) involves combustion occurring inside the main engine core, requiring only clean air to pass through the turbine.
Answer: False
In an externally fired gas turbine (EFGT), the combustion process occurs outside the main engine core. The heated working fluid, typically air, then passes through the turbine, which may prevent contamination of the turbine blades.
Auxiliary Power Units (APUs) are large gas turbines used to power the main propulsion systems of commercial aircraft.
Answer: False
Auxiliary Power Units (APUs) are typically small gas turbines designed to provide auxiliary power, such as compressed air for cabin conditioning and engine starting, rather than powering the main propulsion systems of commercial aircraft.
Industrial gas turbines are characterized by lighter construction and are designed for rapid response, similar to aeroderivative models.
Answer: False
Industrial gas turbines are generally constructed with heavier frames and components and are designed for durability and steady operation, contrasting with the lighter construction and rapid response characteristics of aeroderivative models.
Microturbines spin at significantly lower rotational speeds than large jet engines to achieve efficient operation.
Answer: False
To achieve efficient operation at their smaller scale, microturbines must rotate at considerably higher speeds than large jet engines, often reaching speeds up to 500,000 rpm.
An afterburner injects fuel into the combustor to increase thrust, but it significantly reduces fuel consumption.
Answer: False
An afterburner injects fuel into the exhaust stream, not the combustor, to achieve a significant increase in thrust. This process dramatically increases, rather than reduces, fuel consumption.
The power turbine in a multi-shaft engine extracts energy from the exhaust gases to produce output shaft power, separate from the compressor-driving turbine.
Answer: True
In multi-shaft gas turbine configurations, the power turbine is a distinct turbine stage designed to extract residual energy from the exhaust gases, generating output shaft power independently of the gas generator turbine that drives the compressor.
In turboshaft engines for helicopters, the power turbine drives the gas generator compressor.
Answer: False
In turboshaft engines, the power turbine is responsible for driving the output shaft (which powers the helicopter rotor), while a separate gas generator turbine drives the compressor within the engine core.
Aeroderivative gas turbines are favored for electrical power generation due to their slower response times compared to industrial turbines.
Answer: False
Aeroderivative gas turbines are favored for electrical power generation primarily due to their faster response times and lighter weight compared to traditional industrial turbines, making them suitable for grid stability applications.
The primary difference between a power turbine and a gas generator turbine is that the power turbine drives the compressor.
Answer: False
In a multi-shaft gas turbine engine, the gas generator turbine is coupled to and drives the compressor, forming the core. The power turbine, conversely, extracts energy from the exhaust gases to produce output shaft power.
What is the primary role of a turboprop engine?
Answer: To drive an aircraft propeller
The primary function of a turboprop engine is to drive an aircraft propeller, utilizing a reduction gearbox to match the turbine's high rotational speed to the propeller's optimal operating speed.
How do turbofan engines achieve better fuel efficiency compared to turbojets?
Answer: By utilizing a ducted fan to move bypass air.
Turbofan engines enhance fuel efficiency and reduce noise by incorporating a ducted fan that accelerates a large volume of bypass air around the engine core, contributing significantly to overall thrust.
What distinguishes aeroderivative gas turbines from traditional industrial gas turbines?
Answer: They are based on aircraft engines and are generally lighter.
Aeroderivative gas turbines are derived from aircraft engine designs, resulting in lighter construction and often faster response times compared to the typically heavier and more robust construction of traditional industrial gas turbines.
What are microturbines?
Answer: Small gas turbines typically ranging from 25 to 500 kilowatts.
Microturbines are defined as small gas turbine engines, generally falling within the power output range of 25 to 500 kilowatts.
In an Externally Fired Gas Turbine (EFGT), where does the combustion process take place?
Answer: Outside the main engine
The defining characteristic of an Externally Fired Gas Turbine (EFGT) is that the combustion process occurs externally to the main engine core.
What is the function of an Auxiliary Power Unit (APU) on an aircraft?
Answer: To supply auxiliary power, like compressed air for A/C and starting
An Auxiliary Power Unit (APU) on an aircraft is a small gas turbine that provides essential auxiliary power, including compressed air for air conditioning and engine starting, as well as electrical power for various systems.
How do industrial gas turbines typically differ in construction from aeronautical designs?
Answer: They feature heavier construction for frames and bearings.
Industrial gas turbines are generally characterized by more robust, heavier construction, including frames and bearings, designed for longevity and steady operation, in contrast to the lighter, high-speed designs optimized for aerospace applications.
Why must microturbines rotate at much higher speeds than large gas turbines?
Answer: To compensate for smaller blade size
Microturbines require significantly higher rotational speeds compared to larger gas turbines to achieve the necessary blade tip velocities for efficient compression and expansion, compensating for their smaller physical dimensions.
What is the purpose of an afterburner in a jet engine?
Answer: To inject fuel into exhaust gases to significantly increase thrust.
An afterburner increases thrust by injecting additional fuel into the engine's exhaust stream, where it combusts with residual oxygen, thereby significantly boosting power output, albeit at the cost of substantially increased fuel consumption.
In a multi-shaft gas turbine engine, what is the role of the 'power turbine'?
Answer: To extract remaining energy from exhaust gases for output shaft power.
The power turbine in a multi-shaft gas turbine engine is designed to extract the remaining energy from the exhaust gases after they have passed through the gas generator turbine, converting this energy into useful output shaft power.
What is the primary difference between a 'power turbine' and a 'gas generator turbine' in a multi-shaft engine?
Answer: The gas generator turbine drives the compressor; the power turbine drives the output shaft.
In a multi-shaft gas turbine, the gas generator turbine is directly coupled to and drives the compressor, forming the engine core. The power turbine, situated downstream, extracts energy from the exhaust gases to drive the output shaft.
Gas turbines are exclusively used for powering aircraft and are not found in industrial or transportation sectors.
Answer: False
Gas turbines possess broad applicability, serving not only aircraft propulsion but also numerous industrial applications such as power generation, and various transportation sectors including trains, ships, and land vehicles.
The high power-to-weight ratio is a key advantage of gas turbine engines for aircraft propulsion.
Answer: True
The superior power-to-weight ratio of gas turbine engines is a critical advantage, enabling them to provide substantial thrust relative to their mass, which is essential for efficient aircraft performance.
Gas turbines offer advantages in surface vehicles like cars due to their high power-to-weight ratio and smoother operation.
Answer: True
The high power-to-weight ratio and inherently smoother operation compared to reciprocating engines are significant advantages that make gas turbines suitable for applications in surface vehicles.
Poor fuel efficiency at idle and slow speeds were minor issues that did not significantly hinder the adoption of gas turbines in automobiles.
Answer: False
Poor fuel efficiency at idle and low speeds, coupled with slow throttle response, represented significant challenges that substantially hindered the widespread adoption of gas turbines in automotive applications.
The Chrysler Turbine Car program involved a consumer trial of fifty gas turbine-powered cars featuring a rotating recuperator.
Answer: True
The Chrysler Turbine Car program conducted a notable consumer trial involving fifty vehicles equipped with gas turbine engines, which incorporated a rotating recuperator for enhanced thermal efficiency.
The STP-Paxton Turbocar, using a gas turbine, nearly won the 1967 Indianapolis 500 but faced reliability issues.
Answer: True
The STP-Paxton Turbocar, powered by a gas turbine, demonstrated significant racing potential by nearly winning the 1967 Indianapolis 500, although reliability issues were frequently encountered.
Gas turbines have fewer moving parts than reciprocating engines, contributing to lower maintenance and higher reliability.
Answer: True
A significant advantage of gas turbine engines is their simpler mechanical design, featuring fewer moving parts compared to reciprocating engines, which generally translates to reduced maintenance requirements and enhanced operational reliability.
The Hyperbar system in the French Leclerc tank uses a gas turbine to replace the main diesel engine entirely.
Answer: False
The Hyperbar system in the French Leclerc tank employs a gas turbine as an auxiliary boost system to enhance the performance of the main diesel engine, rather than replacing it entirely.
Gas turbines were largely replaced in large merchant ships by diesel engines due to the turbines' superior fuel economy during constant cruising.
Answer: False
Diesel engines maintained dominance in large merchant ships primarily because they offered superior fuel economy during sustained cruising operations, a critical factor for commercial viability, whereas gas turbines found more application in naval vessels requiring rapid speed changes.
The U.S. Clean Air Act Amendments of 1970 led to reduced government funding for automotive gas turbine research.
Answer: False
Contrary to reducing funding, the U.S. Clean Air Act Amendments of 1970 stimulated government-funded research into automotive gas turbine technology, as manufacturers explored potential solutions for meeting stricter emission standards.
Gas turbines are used in the oil and gas industry primarily to drive pumps and compressors for processes like gas injection.
Answer: True
In the oil and gas industry, gas turbines serve as primary drivers for pumps and compressors, which are essential for critical processes such as gas injection into reservoirs and the compression of natural gas for pipeline transport.
The thrust-to-weight ratio measures an aircraft's weight relative to the engine's thrust output.
Answer: False
The thrust-to-weight ratio quantifies the engine's thrust output in relation to its own weight. A higher ratio is crucial for aircraft performance, indicating greater potential for acceleration and climb.
Natural gas is the primary fuel used in most modern gas-fired power plants, such as the Gateway Generating Station.
Answer: True
Natural gas serves as the predominant fuel source for the majority of contemporary gas-fired power generation facilities, including examples like the Gateway Generating Station.
In desert environments, gas turbines require frequent filter changes due to sensitivity to dust and sand.
Answer: True
Gas turbines are highly sensitive to particulate contamination. In arid environments such as deserts, frequent maintenance, including the replacement of air intake filters, is critical to prevent damage from dust and sand ingress.
Besides aircraft, which of the following is a common application for gas turbine engines mentioned in the source?
Answer: Electric generators
Gas turbine engines are widely utilized in power generation to drive electric generators, in addition to their use in aircraft propulsion.
What is the primary reason gas turbines are highly suitable for aircraft propulsion?
Answer: Their high power-to-weight ratio
The exceptional power-to-weight ratio of gas turbine engines is the principal factor making them highly suitable for aircraft propulsion, as it allows for powerful yet relatively lightweight powerplants.
Which of the following is an advantage of using gas turbines in surface vehicles?
Answer: Compact size
Gas turbines offer several advantages for surface vehicles, including a compact size relative to their power output, a high power-to-weight ratio, and smoother operation.
What was a major challenge that hindered the widespread adoption of gas turbines in automobiles?
Answer: Poor fuel efficiency at idle and low speeds
A significant impediment to the widespread adoption of gas turbines in automobiles was their poor fuel efficiency, particularly at idle and low speeds, along with slower response times compared to conventional piston engines.
What unique feature was incorporated into the Chrysler Turbine Cars for improved efficiency?
Answer: A rotating recuperator (regenerator)
The Chrysler Turbine Cars featured a rotating recuperator (also known as a regenerator), a heat exchanger designed to recover exhaust heat and preheat the incoming compressed air, thereby improving thermal efficiency.
The STP-Paxton Turbocar's near-win at the 1967 Indianapolis 500 highlighted the potential of gas turbines but was often hampered by:
Answer: Reliability issues or rule restrictions
While demonstrating impressive performance, the STP-Paxton Turbocar's racing campaigns were frequently affected by reliability problems, such as gearbox failures, and sometimes by restrictive racing regulations.
Which of the following is listed as a main advantage of gas turbine engines?
Answer: Smoother operation with less vibration
Gas turbine engines offer several advantages, including smoother operation with reduced vibration compared to reciprocating engines, alongside a high power-to-weight ratio and fewer moving parts.
What is the 'Hyperbar' system used for in the French Leclerc tank?
Answer: Providing boost independent of engine RPM via a gas turbine
The 'Hyperbar' system in the French Leclerc tank utilizes a gas turbine to provide boost pressure independently of the main engine's RPM, effectively eliminating turbo lag and enhancing overall performance.
Why did diesel engines remain dominant over gas turbines in large merchant ships?
Answer: Diesel engines offered better fuel economy at constant cruising speeds.
Diesel engines maintained their dominance in large merchant shipping due to their superior fuel economy during sustained cruising operations, a critical economic factor for commercial vessels.
What effect did the U.S. Clean Air Act Amendments of 1970 have on automotive gas turbine research?
Answer: They spurred research funded by the U.S. government.
The U.S. Clean Air Act Amendments of 1970 prompted increased government-funded research into automotive gas turbine technology as manufacturers sought cleaner propulsion alternatives to meet stringent emission regulations.
In the oil and gas industry, gas turbines are primarily used for what purpose?
Answer: Driving pumps and compressors
Within the oil and gas industry, gas turbines are predominantly employed as mechanical drivers for pumps and compressors essential for operations such as gas injection and pipeline compression.
What does the 'thrust-to-weight ratio' measure in the context of flight?
Answer: The engine's thrust output relative to its own weight.
The thrust-to-weight ratio is a critical performance metric that compares the thrust generated by an engine to its own weight. A higher ratio indicates greater potential for acceleration and climb performance in aircraft.
Designing turbine blades for high-temperature gas turbines is challenging primarily due to thermal expansion, which is managed using standard steel alloys.
Answer: False
The primary design challenge for turbine blades in high-temperature gas turbines is managing creep (deformation under stress at high temperatures), not solely thermal expansion. This is addressed using advanced superalloys and specialized coatings, not standard steel alloys.
Thermal barrier coatings (TBCs) are applied to turbine blades to increase their operating temperature by conducting heat away from the superalloy.
Answer: False
Thermal barrier coatings (TBCs) function as thermal insulators, limiting the heat transfer to the underlying superalloy material of the turbine blade. This insulation helps to reduce the blade's operating temperature, thereby mitigating creep and extending its service life.
High core engine costs due to exotic materials are a primary disadvantage of gas turbine engines.
Answer: True
The necessity of employing advanced, high-temperature materials, often termed exotic alloys, for critical engine components contributes significantly to the high manufacturing cost of gas turbine cores, representing a primary economic disadvantage.
Single-crystal superalloys improve creep resistance in turbine blades by impeding dislocation motion, allowing higher operating temperatures.
Answer: True
The use of single-crystal superalloys in turbine blades significantly enhances creep resistance. Their unique microstructure impedes dislocation motion, thereby increasing the material's ability to withstand stress at elevated temperatures and permitting higher operating temperatures.
Foil bearings, introduced commercially in the 1990s, eliminated the need for oil systems in all gas turbine applications.
Answer: False
While foil bearings, commercially introduced in the 1990s, have eliminated the need for traditional oil systems in certain gas turbine applications, particularly microturbines, they have not rendered oil systems obsolete in all applications.
The 'yield strength anomaly' in some superalloys means they become weaker at higher temperatures, necessitating lower operating limits.
Answer: False
The 'yield strength anomaly' observed in certain superalloys indicates that they actually become stronger at higher temperatures. This property enhances their performance and allows for higher operating limits in demanding applications like turbine blades.
The Hall-Petch relationship explains how grain boundaries strengthen materials, which is why single-crystal superalloys are less resistant to creep.
Answer: False
The Hall-Petch relationship posits that grain boundaries enhance material strength by impeding dislocation movement. Single-crystal superalloys, by eliminating grain boundaries, are engineered to improve high-temperature creep resistance, contrary to the statement.
What is the main challenge in designing turbine blades for high-temperature gas turbines?
Answer: Reducing creep deformation
The primary challenge in designing turbine blades for high-temperature gas turbines is mitigating creep, which is the time-dependent deformation of materials under sustained stress at elevated temperatures.
How do thermal barrier coatings (TBCs) protect turbine blades?
Answer: By providing thermal insulation to limit temperature exposure.
Thermal barrier coatings (TBCs) act as thermal insulators, reducing the rate at which heat is transferred to the underlying superalloy material of the turbine blade, thereby protecting it from excessive temperatures.
What is identified as a primary disadvantage of gas turbine engines?
Answer: Potentially high core engine costs
The utilization of advanced, high-performance materials required for the core components of gas turbine engines contributes to their potentially high manufacturing costs, which is identified as a primary disadvantage.
How do single-crystal superalloys improve the performance of turbine blades?
Answer: By improving resistance to creep at high temperatures
Single-crystal superalloys enhance turbine blade performance by significantly improving resistance to creep at high temperatures, allowing for higher operating temperatures and increased engine efficiency.
What advantage do foil bearings offer in certain gas turbine applications?
Answer: They can withstand many start/stop cycles and eliminate the need for oil systems.
Foil bearings, particularly in applications like microturbines, offer the advantage of withstanding numerous start/stop cycles and can eliminate the requirement for traditional lubrication oil systems.
A combined cycle power plant enhances efficiency by using waste heat from a gas turbine to generate steam for a separate steam turbine.
Answer: True
Combined cycle power plants achieve higher overall thermal efficiency by integrating a gas turbine with a steam turbine system, utilizing the exhaust heat from the gas turbine to produce steam for the steam turbine.
A recuperator preheats compressed air using ambient air before it enters the combustor, increasing engine efficiency.
Answer: False
A recuperator functions as a heat exchanger that preheats the compressed air using heat recovered from the exhaust gases, not ambient air. This preheating process enhances the engine's overall thermal efficiency.
A simple-cycle gas turbine used solely for shaft power typically achieves a thermal efficiency of around 60%.
Answer: False
Simple-cycle gas turbines operating solely for shaft power typically exhibit thermal efficiencies in the range of 30-40%. Efficiencies approaching 60% are characteristic of advanced combined-cycle power plants.
The Mitsubishi Heavy Industries M501J gas turbine, tested in 2011, was the first combined cycle unit to exceed 60% efficiency.
Answer: True
The Mitsubishi Heavy Industries M501J gas turbine achieved a significant technological milestone in 2011 by becoming the first combined cycle unit to demonstrate a thermal efficiency exceeding 60%.
Combined heat and power (CHP) systems utilize waste heat for heating or cooling, increasing overall energy utilization efficiency.
Answer: True
Combined Heat and Power (CHP) systems, also known as cogeneration, significantly enhance overall energy utilization efficiency by capturing waste heat from the gas turbine and applying it to secondary uses such as space heating, water heating, or absorption chilling.
What is the key principle behind a combined cycle power plant?
Answer: Using exhaust heat to generate steam for a steam turbine.
The fundamental principle of a combined cycle power plant involves utilizing the waste heat from a gas turbine's exhaust gases to generate steam, which then drives a separate steam turbine, thereby increasing overall energy conversion efficiency.
What is the function of a recuperator in a gas turbine engine?
Answer: To preheat compressed air using exhaust heat
A recuperator functions as a heat exchanger that preheats the compressed air entering the combustor by utilizing heat recovered from the engine's exhaust gases, thereby improving thermal efficiency.
What is the typical efficiency of a simple-cycle industrial gas turbine used solely for shaft power?
Answer: Approximately 30%
A simple-cycle industrial gas turbine operating solely for shaft power typically achieves a thermal efficiency in the range of 30% to 40%.
What advancement did the Mitsubishi Heavy Industries M501J gas turbine represent in 2011?
Answer: The first combined cycle gas turbine to achieve over 60% efficiency.
In 2011, the Mitsubishi Heavy Industries M501J gas turbine marked a significant technological achievement by becoming the first combined cycle gas turbine unit to surpass 60% thermal efficiency.
What is the 'combined heat and power' (CHP) configuration, also known as cogeneration?
Answer: Utilizing waste heat for other purposes like heating or cooling.
Combined Heat and Power (CHP), or cogeneration, is an energy-efficient process that utilizes the waste heat generated by a gas turbine for secondary applications such as space heating, water heating, or driving absorption chillers for cooling.
Computational Fluid Dynamics (CFD) is used to analyze fluid flow and heat transfer, improving gas turbine component performance.
Answer: True
Computational Fluid Dynamics (CFD) is an indispensable tool in modern gas turbine design, enabling detailed analysis of complex fluid flow and heat transfer phenomena to optimize component performance and overall engine efficiency.
ASME Performance Test Codes, like PTC 22-2014, standardize testing procedures and use uncertainty measurements as commercial tolerances.
Answer: False
ASME Performance Test Codes, such as PTC 22-2014, standardize gas turbine testing procedures. However, they utilize uncertainty measurements to indicate the quality and reliability of the test results, rather than as commercial tolerances.
A turbocharger functions as a compact gas turbine driven by exhaust gas to force more air into an engine's intake.
Answer: True
A turbocharger operates on the principle of a gas turbine, utilizing the energy from exhaust gases to drive a turbine wheel. This wheel, in turn, powers a compressor that forces additional air into the engine's intake manifold, thereby increasing power output.
A wastegate controls the flow of exhaust gas to the turbocharger's turbine to manage boost pressure.
Answer: True
A wastegate is a valve that regulates the flow of exhaust gas directed to the turbocharger turbine. By controlling turbine speed, it effectively manages the boost pressure delivered to the engine, preventing over-boosting.
The Wobbe index is a measure used to ensure the interchangeability of different fuel gases for turbines.
Answer: True
The Wobbe index is a key parameter used to assess the interchangeability of various fuel gases, ensuring that different gas compositions can be utilized in gas turbines without requiring substantial operational adjustments.
Air cycle machines use compressed air from an APU to provide cooling for aircraft cabins.
Answer: True
Air cycle machines utilize compressed air, often supplied by an aircraft's Auxiliary Power Unit (APU), to generate cooling for cabin environmental control systems through thermodynamic expansion processes.
What role does Computational Fluid Dynamics (CFD) play in gas turbine development?
Answer: Analyzing fluid flow and heat transfer phenomena
Computational Fluid Dynamics (CFD) is instrumental in gas turbine development, enabling detailed analysis of fluid flow and heat transfer characteristics to enhance the performance and efficiency of engine components.
What is a key characteristic of ASME Performance Test Codes regarding uncertainty?
Answer: They indicate test quality through uncertainty measurements.
ASME Performance Test Codes, such as PTC 22-2014 for gas turbines, employ uncertainty measurements primarily to quantify and indicate the quality and reliability of the test results, rather than establishing them as commercial tolerances.
How does a turbocharger increase an engine's power output?
Answer: By using exhaust gas energy to drive a compressor that forces more air into the intake.
A turbocharger increases engine power by harnessing exhaust gas energy to drive a compressor, which then forces a greater volume of air into the engine's cylinders, enabling more complete fuel combustion.
What is the 'Wobbe index' used for in relation to fuel gas for turbines?
Answer: Ensuring the interchangeability of different fuel gases.
The Wobbe index is a critical measure used to determine the interchangeability of different fuel gases, ensuring that variations in fuel composition do not adversely affect gas turbine performance or operation.