1 - LM2500 GAS TURBINE ENGINE (GTE) Flashcards
How much Brake Horse Power (BHP) does the LM2500 produce?
26,250 BHP
How does the Gas Generator (GG) work?
Receives air, at ambient temps. and pressure, and produces a stream of rapidly expanding hot gases that drive the Power Turbine (PT)
How does the Power Turbine (PT) work?
Drives the MRG and propeller shaft, via a High Speed Flexible Coupling Shaft (HSFCS)
Characteristics about the GG and PT
Aerodynamically coupled
As GG speed changes, PT speed changes proportionally
Characteristics of the GG
Four major assemblies
1. 16-stage axial flow Compressor
2. Annular type Combustor
3. 2-stage High Pressure Turbine (HPT)
4. Accessory Gearbox (AGB)
What components make up the Compressor Assembly?
- Compressor Front Frame (CFF)
- Compressor Stator
- Compressor Rotor
- Compressor Rear Frame (CRF)
Compressor Stator specs
- One stage of Inlet Guide Vanes (IGV)
- Six stages of Variable Stator Vanes (VSV)
- 10 Stages of Stationary Vanes
Angular positions are controlled by two “torque motors”
- Utilize 23699 synthetic lube oil
Helps control the amount of air flowing through the engine
Compressor Rotor specs
- 16 Stages of blades before entering combustion section
Compressor Rear Frame (CRF) specs
- House the annular combustor
- Mount and support the fuel manifold and 30 fuel nozzles
- Mount the two spark igniters
- Mount the customer service bleed air manifold
- House the B-sump with no. 4 ball and no. 4 roller bearing
Annular Combustor specs
Located inside the CRF, made up of four structural elements
1. Forward Cowl
2. Dome
3. Inner Liner
4. Outer Liner
30% of airflow is utilized for actual combustion
70% is used used for cooling and flame stabilization
Produces hot expanding gases to drive HP and LP turbines
High Pressure (HP) Turbine specs
Drives the compressor; rotated by the energy created by expanding gasses leaving the chamber
Consists of two nozzle assemblies and a spool type two-stage rotor
Power Turbine (PT) specs
6-stage turbine
Drives the shaft
Aerodynamically couple to the HP turbine
Drives the HSFCS which drives the MRG input shaft
Accessory Gearbox (AGB) specs
Driven by power transmited from the Transfer Gear Box (TGB), via a radial drive shaft, and Inlet Gear Box (IGB)
Drives the GTM accessories
Digital Fuel Control (DFC) specs
Consisted of:
- Hydraulic Pump
- VSV Servo Valve assembly
- Fuel Metering Valve & Actuator
- VSV Actuators
- Accumulator
Controls amount of F/O fed into the combustor
GTM Frames
Primary load bearing members of the engine
7 main bearings
Bearings - Roller, Ball
Roller bearings - 5 per GTM; controls rotational (radial) force of the engine
Ball bearings - 2 per GTM; controls axial thrust force of the engine
How are bearings retained?
4 Main engine sumps
- A - located in the CFF; contains #3R bearing
- B - located in the CRF; contains #4R & #4B bearings
- C - located in the Turbine Mid Frame (TMF); contains #5R & #6R bearings
- D - located in the Turbine Rear Frame (TRF); contains #7R & #7B bearings
Bleed Air Stages
8th Stage - used for sump pressurization and cooling of the four bearing sumps
9th Stage - used to cool the PT balance piston in the TRF, cool the TMF struts, and LP turbine rotor
13th Stage - used to cool the 2nd stage HP turbine nozzles and interstage seals
16th Stage (Customer Bleed Air) - used for cooling the combustor lining and centering the flame in the Combustion Chamber
Importance of the 16th Stage in the Compressor
Creates “Customer Bleed Air”
Used when Gas Generator Speed (Ngg) is >7500 rpm for Start air, Prairie air, Anti-icing air, and Masker air (SPAM)
What Cycle does the GTE use?
Brayton Cycle
Suck, Squeeze, Bang, Blow
