Turbine Block 13 Practice Exam

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• What is a combined cycle, and how does integrating a gas turbine with a steam turbine improve overall efficiency?
• What happens to the pressure of supersonic air as it flows through a divergent nozzle?
• In the Brayton cycle, which component is primarily responsible for expanding high-pressure gas to produce shaft power?
• What is the major function of the turbine assembly in a turbojet engine?
• Define heat rate in a turbine context and its relation to efficiency.
• What is the importance of seals and gaskets in turbine assemblies, and what damage can be caused by seal failures?
• In the compressor section of an axial-flow engine, what is the primary effect of the stator vanes?
• The basic gas turbine engine is divided into cold and hot sections. The cold section includes which components?
• In a compressor section, what is the purpose of the stator vanes?
• When starting a turbine engine, a hot start is indicated by
• Which option is NOT a typical method to control Turbine Inlet Temperature (TIT)?
• Dirt particles entering the compressor will coat all but which component?
• Bleed air used for anti-icing is typically taken from which part of the engine?
• What is the most likely cause when a turbine engine shows no change in power setting parameters, but oil temperature is high?
• Tip clearance is defined as the gap between which components?
• Hot section inspections for many modern turbine engines are required on what basis?
• Which method is commonly used to anti-ice jet engine inlets?
• How does exhaust temperature impact the backpressure on a turbine and overall performance?
• Which of the following are common safety interlocks in turbine control systems?
• What is the primary function of the diffuser in a centrifugal compressor?
• Hot spots on the tail cone of a turbine engine are possible indicators of?
• As compressor pressure ratio increases, the main effect on the compressor work is:
• If a turbine engine is unable to reach takeoff EPR before its EGT limit is reached, this indicates what?
• Which symptom indicates the compressor may be contaminated or damaged when attempting to reach takeoff thrust?
• How should blade blending be performed?
• In what scenario might SCR be used?
• Why is CO formation a concern in lean-burn gas turbines and how is it controlled?
• Why is ramp rate to idle speed limited during start-up and what could happen if ramp is too fast?
• The purpose of the shrouds on the turbine blades of an axial-flow engine is to?
• What is TBC in turbine technology and why is it used?
• In turbine engine terminology, Pt7 denotes which quantity?
• Which blade type operates primarily by impulse action?
• An exhaust cone placed aft of the turbine in a jet engine will cause the pressure in the first part of the exhaust duct to
• What is the role of nozzle guide vanes in a turbine and how do they interact with rotor blades?
• Bleed air is used to maintain surge margin by which action?
• Which of the following best characterizes typical safety interlocks in gas turbine control systems?
• Blade blending is intended to achieve which outcome in turbine blades?
• Newton's First Law of Motion is commonly known as the Law of Inertia. Which statement best describes it?
• What is field cleaning?
• Which device is used to inspect internal components of an assembled turbine engine without disassembly?
• What may be used to accomplish internal inspection of an assembled turbine engine?
• Which turbine engine compressor offers the greatest advantages for starting flexibility and improved high altitude performance?
• Which two signs indicate corrosion-related blade damage?
• What is the purpose of borescope inspections in turbine maintenance?
• What is the first instrument indication of a successful start of a turbine engine?
• The diffuser is located immediately downstream of which section?
• Which component is primarily responsible for diffusing the air between rows of rotating blades in a turbine engine compressor?
• Severe rubbing of turbine engine compressor blades will usually cause which wear mechanism?
• Turbine nozzle diaphragms located upstream of each turbine wheel are used to do what to the gases flowing past this point?
• What is the diffuser's effect on the incoming air in terms of flow and pressure?
• What is the purpose of water wash in gas turbines and when is it performed?
• Which marking material is commonly allowed for high-temperature turbine components?
• In an axial-flow turbine section, the rotor and stator perform which pair of roles?
• What is the primary mechanism by which acoustic liners reduce noise in turbine engines?
• The turbine engine hot section is particularly susceptible to which kind of damage?
• Which factor is most critical to turbine engine operation, demanding strict control?
• What causes combustion instability in turbine combustors and how is it mitigated?
• Which two main sections compose a basic gas turbine engine?
• During combustion in a gas turbine engine, the process occurs at what pressure condition?
• Which statement best describes welding and straightening of turbine engine rotating air foils?
• In the dual axial-flow or twin spool compressor system, the first stage turbine drives which compressor?
• Bleed air in turbine systems is used for which of the following purposes?
• How do modern turbines detect approaching surge, and what actions are taken to prevent it?
• In high-temperature blade alloys, which property is most crucial to resist creep at elevated temperatures?
• Which type of turbine blade is most commonly used in aircraft jet engines?
• What is turbine governing and how does it respond to load changes?
• Which statement best describes exhaust temperature's effect on backpressure and efficiency?
• Which engine section is primarily responsible for mixing fuel and air before combustion?
• The turbine section of a jet engine drives which section?
• Purge gas during turbine shutdown serves to:
• Which of the following is the ultimate limiting factor of turbine engine operation?
• An advantage of the axial-flow compressor is its
• Which factor primarily explains why turbine blades are more susceptible to operating damage than compressor blades?
• Bleed air is typically bled from which source in a gas turbine?
• The function of a labyrinth seal in a turbine is to:
• In a gas turbine engine, combustion occurs under what pressure condition?
• During startup of a turbine engine, the starter is typically disengaged after the engine reaches which speed characteristic?
• In an axial-flow compressor stage, what two components comprise the stage?
• What is the function of internal cooling channels in turbine blades?
• The diffuser, which is the combustion inlet, is located immediately downstream of which component?
• In high-temperature turbine blade alloys, which property is commonly prioritized to resist oxidation, creep, and fatigue?
• Where is the highest gas pressure in a turbojet engine?
• Which statement is true about jet engine thrust as engine speed increases?
• Which condition is most critical to turbine engine operation, requiring strict control?
• Which of the following is used to aid stabilization of compressor air flow during low thrust operation?
• The stator vanes in an axial-flow compressor convert ______ energy into ______ energy.
• What is the purpose of degaussing magnetized bearings?
• Which factor is most closely associated with the development of stress rupture cracks in turbine blades?
• In a combined cycle, how is exhaust used to improve efficiency?
• Which of the following can be used to stabilize compressor airflow during low thrust operation?
• In a turbine engine, main bearing oil seals are usually of which type?
• Rotor unbalance in a turbine manifests as what symptom, and what method mitigates it?
• During turbine engine operation, which engine variable is considered the most critical?
• What is the primary purpose of shrouds on turbine blades?
• Which two elements make up a single stage of the axial-flow compressor?
• What does Engine Pressure Ratio (EPR) refer to?
• The number of rows of stages in an axial-flow compressor is determined by which two quantities?
• The Brayton cycle is known as the what cycle?
• What is the proper starting sequence for a turbojet engine?
• Which statement best describes the law commonly referred to as the Law of Inertia?
• What are the two functional elements in a centrifugal compressor?
• Which failure mode is most associated with overheating turbine blades?
• What is the function of the inlet guide vane assembly on an axial-flow compressor?
• An exhaust cone placed aft of the turbine affects the first part of the exhaust duct by
• Which component is in the cold section but not in the hot section?
• In high-altitude operation of two-spool engines, which rotor tends to increase in speed as the compressor load decreases?
• The diffuser section of a jet engine is located between which two sections?
• The self-accelerating speed in engine starting is best described as?
• Transpiration cooling differs from film cooling in that:
• Why are acoustic liners used in certain turbine combustors or casings, and how do they function?
• Who establishes mandatory replacement times for critical components of turbine engines?
• During inspection, turbine engine components exposed to high temperatures may only be marked with such materials as allowed by the manufacturer. These materials may generally include
• Which instrumentation is critical for turbine operation and monitoring?
• What diagnostic methods are used to assess turbine health, including non-destructive testing?
• If stress rupture cracks are found on the leading edge of a first-stage turbine blade, what condition should be suspected?
• Main bearing oil seals used with turbine engines are usually what types?
• Which combustor configuration allows modularity by combining can and annular features?
• In an axial-flow compressor, which pair forms a pressure stage?
• When aircraft turbine blades are subjected to excessive heat stress, what type of failures would you expect?
• What is the primary purpose of Thermal Barrier Coatings in turbines?
• In a dual-spool compressor, the low speed compressor seeks...
• The compressor stators in a gas turbine engine act as diffuser to...
• What does the term double entry centrifugal compressor refer to?
• How does soot deposition affect turbine efficiency and which cleaning method helps?
• How can fuel quality impact turbine operation, including deposits and corrosion?
• How does inlet anti-ice control access to the compressor and what are typical heat sources?
• Anti-icing of jet engine inlets is commonly achieved by which method?
• A gas turbine engine comprises which three main sections?
• Why is reheat rarely used in industrial gas turbines?
• When jet engine turbine blades are removed for detailed inspection, how must they be reinstalled?
• In fuel scheduling, what protective functions does the engine control provide?
• The air passing through the combustion chamber of a turbine engine is used to?
• How are maintenance intervals for turbines typically determined, and what factors influence them?
• In twin-spool gas turbine engines, turbine discharge pressure is identified in maintenance manuals as what?
• Which blade type is described as combining impulse and reaction characteristics?
• The turbine bearing lubrication system is responsible for:
• Turbine Inlet Temperature (TIT) is a critical design and operating limit because:
• Which option lists the three types of turbine blades?
• Which combination of methods is commonly used to assess turbine health?
• Compressor field cleaning on turbine engines is performed primarily in order to prevent?
• Recurrent ingestion of dust or other fine airborne particulates into a turbine engine can result in what type of damage?
• A turbine engine compressor with vanes on both sides of the impeller is known as what type?
• Which of the following is not a type of centrifugal compressor impeller?
• Which section provides for proper mixing of fuel and air in a gas turbine engine?
• Which statements are true regarding aircraft engine propulsion?
• The stators in the turbine section of a gas turbine engine do what?
• What is the purpose of monitoring sensors during startup and ramping to full speed?
• Through a convergent nozzle, the velocity of supersonic air tends to do what?
• Which statement about the convergent nozzle for subsonic flow is true?
• Which cooling method is described as coolant permeating through the blade from inside to provide internal cooling?
• In a compressor, the bleed valve located at the initial stages serves to vent some air overboard to prevent what condition?
• How do designers accommodate thermal expansion differences between turbine components?
• What are common combustor configurations in modern gas turbines and their advantages?
• What is the purpose of external cooling, or film cooling, in turbine blades?
• Which statement best describes an advantage of the centrifugal-flow compressor?
• The hot section includes which components?
• Bleed air vented from the early compressor stages is used to prevent which condition?
• In an axial-flow compressor, the stator vanes primarily perform which action on the flow?
• What is the diffuser's primary effect on the airflow?
• The stator vanes convert velocity energy into which form of energy?
• How does fuel scheduling interact with interstage temperature (IT) and RPM to maintain safe operation?
• The non-rotating axial-flow compressor air foils in an aircraft gas turbine engine are called?
• Which action is commonly taken to prevent surge when sensors indicate a reduced surge margin?
• Primary blade cooling methods in a gas turbine include:
• The two types of centrifugal compressor impellers are?
• What is the Brayton cycle in a gas turbine system?
• Using standard atmospheric conditions, the standard sea level temperature is?
• Which statement about engine starts is true?
• What are the two basic elements of an axial-flow turbine section in a turbine engine?
• What is rotor critical speed and why is it important for turbine operation?
• What is the role of the FADEC in fuel scheduling and IT control?
• In an axial-flow turbojet engine, where do the highest gas pressures occur?
• If bearings are magnetized but otherwise defect-free, what must be done before use?
• Hot section inspections are scheduled based on which factors?
• A weak fuel-to-air mixture along with normal airflow through a turbine engine may result in which condition?
• In the turbine section, what component is installed to direct and shape the gas flow onto the rotor blades?
• What is the purpose of purge during startup?
• For a dual axial compressor forward fan engine, the fan rotational speed is the same as which compressor speed?
• In modern turboprop engines, what percentage range of exhaust gas energy is typically extracted by turbines to drive the propeller and compressor?
• What happens to the pressure of subsonic air as it flows through a divergent nozzle?
• The velocity of subsonic air as it flows through a convergent nozzle increases or decreases?
• Who establishes the recommended operating time between overhauls (TBO) of a turbine engine used in general aviation?
• What is the role of selective catalytic reduction (SCR) in gas turbines, and when might it be used?
• Which component does the turbine section primarily power in a turbojet engine?
• In turbine design, are nozzle guide vanes stationary or rotating, and what is their primary function?
• What is the primary factor that controls the pressure ratio of an axial-flow compressor?
• Which of the following is a blade damage sign to look for during borescope inspection?
• Which sequence best describes a typical safe gas turbine shutdown?
• What is the function of diluent air in lean-burn combustors and how does it affect NOx formation?
• Turbine engine components exposed to high temperatures generally may not be marked with which marking?
• What is the primary advantage of an axial-flow compressor over a centrifugal compressor?
• Reducing tip clearance generally results in which trade-off?
• Which sequence best describes a typical safe gas turbine start?
• Between each row of rotating blades in a turbine engine compressor, there is a row of stationary vanes which act to diffuse the air. The stationary blades are called?
• In some high-volume two-spool engines, when operated at high altitude, what happens to the low-pressure rotor as compressor load decreases in low-density air?
• What should be done initially if a turbine engine catches fire?
• Which statement about the diffuser action of the compressor stators is true?
• During routine maintenance, in which combustion chamber type is the case and liner removed and installed as one unit?
• What is the function of the stator vane assembly at the discharge end of a typical axial-flow compressor?
• What does the term 'profile' refer to for a turbine engine compressor blade?
• What is the primary function of the compressor in a turbine engine?
• Where is the highest heat-to-metal contact in a jet engine?
• After replacing the fuel control unit on an aircraft gas turbine engine, what must be done?
• Reduced blade vibration and improved air flow characteristics in gas turbines are achieved by what design feature?
• What is the purpose of inlet air filtration and how does fouling affect turbine performance?
• What triggers an overspeed trip in turbine control?
• In a gas turbine engine, which section is primarily responsible for converting chemical energy into high-energy gases that do the work?
• In an axial-flow compressor, the purpose of the stator vanes at the discharge end of the compressor is to?
• Dirt particles entering the compressor will form a coating on all but which component?
• Increasing compressor pressure ratio in a gas turbine cycle generally:
• When starting a turbine engine, a hung start is indicated if
• Which wear mechanism is associated with severe rubbing of compressor blades?
• Standard sea level pressure is?
• In an axial-flow compressor stage, which component is stationary?
• Which statement best describes how a dual axial-flow compressor improves turbojet efficiency?
• The Brayton cycle in gas turbine propulsion is best described as a constant pressure cycle. Which option correctly completes this statement?
• Where do stress rupture cracks usually appear on turbine blades?
• During shutdown, why is purge performed after cooldown?
• Which statement about heat rate is false?
• What is an advantage of the centrifugal-flow compressor?
• The function of the exhaust cone assembly of a turbine engine is to
• Routine oil system maintenance tasks include: