Subject B - Turbine Engines Flashcards
what are the major components of a typical gas turbine engine?
A typical gas turbine engine consists of an air inlet, compression section, combustion section, turbine section, exhaust section, and accessory section.
What are the two main principle types of compressors used in turbojet aircraft.
the two most common types of compressors are centrifugal flow and axial flow types.
What are the four combustion chamber systems?
They are can, can-annular, annular, and reverse flow annular types.
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 the 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 of the liner.
what types of damage may be found when inspecting compressor blades?
burns, burrs, cracks, dents, , gouges, galling, pittings, and scratches
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 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, fir-tree, or dove tail type roots. The blades are then locked by means of keys, locking wires, peening, pins, and screws,
what is the purpose of the nozzle diaphragm, or turbine nozzle.
The turbine nozzle prepares the combustion mass airflow to drive the turbine rotor. 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 rotaion.
what is the major difference between the turboprop and turbojet engines?
A turboprop engine usually has more turbine stages than a 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 in principle is 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.
If density increases thrust increases and vice versa.
An increase in air temp entering an engine will cause a decrease in air density and thrust.
an increase in air pressure entering the engine will cause an increase in air density and thrust.
What are the two most common types of thrust reverse?
They are mechanical blockage type and 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.
