WorksheetsTEST 10 – Gas Turbines and Jet Engines
Total questions: 26
Worksheet time: 13mins
Which cycle modification lowers compressor work?
Intercooling
Regeneration
Reheating
Afterburning
Which turbine stage extracts energy to drive the compressor?
Power turbine
Gas generator turbine
Free turbine
Diffuser
What is the role of a combustor liner?
To cool turbine blades
To provide stable flame and protect outer casing
To increase turbine work
To filter air
Which method improves part-load operation in advanced gas turbines?
Variable stator vanes
Water injection only
Increased inlet temperature
Short exhaust stack
Which factor increases specific power output of gas turbines?
High turbine inlet temperature
High exhaust pressure
Low pressure ratio
High lube oil flow
Which efficiency is used to evaluate compressor stage performance?
Isothermal efficiency
Isentropic efficiency
Volumetric efficiency
Mechanical efficiency
What is the function of turbine shrouds?
To reduce tip leakage and improve efficiency
To cool turbine blades
To increase exhaust velocity
To lower emissions
What is the usual firing order in multiple combustor gas turbines?
Sequential
Random
Simultaneous
Cyclic
Which property of fuel is most important for gas turbines?
Cetane number
High calorific value and clean burning
High viscosity
Low octane number
What is the primary pollutant formed at high turbine inlet temperatures?
CO
HC
NOx
SO2
Which system removes unburnt fuel during shutdown?
Drain valves
Diffuser
Compressor bleed
Lube oil separator
Which loss dominates at part-load in gas turbines?
Mechanical losses
Heat transfer losses
Combustion inefficiency and throttling
Radiation losses
Which gas turbine cycle uses a closed loop with helium as working fluid?
Nuclear gas turbine cycle
Air standard Brayton
Diesel cycle
Otto cycle
What is the usual power factor of gas turbine generators?
0.5
0.7
0.8–0.9
1.0
Which system maintains constant generator frequency?
Voltage regulator
Speed governor
Cooling water pump
Exhaust diffuser
What is the unit of heat rate in gas turbines?
kWh/kg
kJ/kWh
kg/kWh
W/m^2
Which factor influences turbine blade creep life most?
Fuel flow
Temperature and stress
Vibration only
Emissions
Which technique reduces NOx without water injection?
Dry low-NOx combustor
Steam cooling
Regeneration
Reheating
What is the advantage of combined cycle gas turbine plants?
Low exhaust temperature
High efficiency by recovering exhaust heat in a steam cycle
Lower capital cost than simple cycle
No cooling required
Which number defines ratio of actual cycle efficiency to ideal cycle efficiency?
Performance factor
Efficiency ratio
Work ratio
Utilization factor
Which part of the gas turbine plant experiences highest temperature?
Compressor inlet
Combustor exit (turbine inlet)
Diffuser
Exhaust stack
Which type of turbine is used in aircraft jet engines?
Radial flow
Axial flow
Reaction turbine
Pelton turbine
Which modification increases both power output and efficiency?
Combined cycle operation
Regeneration alone
Intercooling alone
Afterburning
What is the unit of specific thrust in jet gas turbines?
N·s/kg
kJ/kg
kW/kg
J/mol
Which factor reduces part-load performance in simple gas turbines?
Reduced pressure ratio
High regeneration
Variable geometry
High efficiency combustor
Which part converts kinetic energy of jets to thrust in jet engines?
Nozzle
Compressor
Combustor
Intercooler
