TURBINE ENGINES Flashcards
What are the major components of a typical gas turbine engine?
A typical gas turbine engine consists of an air inlet, a compression section, a combustion
section, a turbine section, an exhaust section, and the accessory section, a turbine section, an
exhaust section, and the accessory section.
What are the two principle types of compressors used in turbojet aircraft?
The two most common compressors in use today are the centrifugal flow and the axial flow
types.
What are three types of combustion chamber systems
They are the can type, the can-annular type, and the annular type
What is the purpose of the interconnector tubes between can-type combustion chambers?
To spread the flame to the combustion chambers that are not equipped with igniter plugs during
engine starting
What prevents burning of the liner walls in can-type combustion chambers?
Louvers are provided along the axial length of the liners to direct a cooling layer of air along the
inside wall of the liner.
What types of damage may be found when inspecting compressor blades?
Dents, scratches, gouges, galling, burns, burrs, pitting, and cracks
What is the location and function of the diffuser section in a turbine engine?
The diffuser is the divergent section of the engine located between the compressor section and
the burner cans. Its function is to change the high-velocity compressor discharge air to static
pressure.
Where are stress rupture cracks most likely to occur on turbine blades?
They usually appear as small hairline cracks on or across the leading or trailing edge of the
blades. The cracks appear at right angles to the edge length.
How are compressor blades attached to a disk-type rotor?
The compressor blades are fitted into the disks by either bulb-type or fir tree-type roots. The
blades are then locked by means of screws, peening, locking wires, pins, or keys.
What is the purpose of the nozzle diaphragm or turbine nozzle?
The turbine nozzle prepares the combustion mass airflow to drive the turbine rotor. First, they
change a portion of the heat and pressure energy to velocity energy. The fixed vanes are
shaped and set at such an angle that they form a number of small nozzles that discharge the
gases at extremely high speeds. The second purpose of the turbine nozzle is to deflect the
gases so they strike the turbine at the most efficient angle for maximum turbine rotation.
What is the major difference between a turboprop and a turbojet engine?
A turboprop engine usually has more turbine stages than the turbojet engine. In addition to
operating the compressor and accessories, the turboprop turbine must also drive a propeller.
What is a turbofan engine?
A turbofan engine is, in principle, the same as a turboprop except that the propeller is replaced
by a duct-enclosed axial flow fan.
What is the effect of air density on the thrust of a turbine engine?
Air density determines the mass of air that is used by a jet engine? The factors that affect
density are the temperature and pressure of the air. If density increases, thrust increases, and
vice versa. An increase in air temperature entering an engine will cause a decrease in density
and thrust. An increase in air pressure entering the engine will cause an increase in density and
thrust. With a given throttle setting, engine thrust will vary if the temperature or pressure of the
air entering the engine changes.
What are the two most common types of thrust reverse?
The mechanical blockage type and the aerodynamic blockage type
What is a split compressor system in a turbine engine?
The split compressor system requires two concentric shafts joining the turbine stages to their
respective compressors.
