Gas Turbine Engine Theory Flashcards
7 cards from real AME practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Gas Turbine Engine Theory flashcards as text
In a gas turbine engine, where does the highest total pressure in the gas path occur?
Answer: At the compressor discharge (diffuser outlet)
Total pressure peaks at compressor discharge and drops slightly through the combustor due to flow losses.
What is the primary purpose of the diffuser section located between the compressor and combustor?
Answer: Decrease velocity and increase static pressure
The divergent diffuser slows airflow so the flame can be stabilized and static pressure rises.
Approximately what percentage of the air entering a typical combustor is used directly for combustion (primary air)?
Answer: About 25%
Roughly 25% is primary combustion air, while about 75% is secondary air used for cooling and dilution.
Which change in ambient conditions will increase the thrust output of a turbojet engine?
Answer: Lower outside air temperature
Colder air is denser, increasing mass airflow and thrust.
What is the function of the nozzle guide vanes located ahead of the first turbine stage?
Answer: Accelerate the gases and direct them at the correct angle onto the turbine blades
The convergent passages of the NGVs raise velocity and set the correct flow angle for the turbine blades.
In a dual-spool axial flow engine, the low-pressure compressor (N1) is driven by which component?
Answer: The low-pressure turbine
The LP turbine drives the LP compressor through the inner concentric shaft.
What does 'bypass ratio' describe in a turbofan engine?
Answer: Ratio of air mass flowing through the fan duct to air mass flowing through the core
Bypass ratio is the mass of bypass air divided by the mass of core air.