Upload
horatio-butler
View
265
Download
1
Embed Size (px)
Citation preview
1
MAE 4261: AIR-BREATHING ENGINES
Overview of Axial Compressors
Mechanical and Aerospace Engineering Department
Florida Institute of Technology
D. R. Kirk
2
TWO PRIMARY TYPES OF COMPRESSORS
• Radial (Centrifugal) Devices– Can not handle as high mass flow– Less efficient than axial device– Short length– Robust– Less Parts
• Axial Devices– High mass flow– High efficiency– Stackable (multi-staging)– More parts– More complex
3
CENTRIFUGAL COMPRESSORS
4
ALLISON 250: AXIAL + RADIAL DEVICE
5
WHERE IN THE ENGINE? PW2000
FanCompressor
6
2 SPOOL DEVICE: PW2000
High Pressure Compressor (high)
Low Pressure Compressor (low)
High and Low Pressure Turbines
7
SCHEMATIC REPRESENTATION
Single Shaft Compressor
Twin-Spool Turbofan
8
2 SPOOL DEVICE
Low Pressure Spool
Low Pressure Compressor High Pressure Compressor
9
FEATURES OF INTEREST: PW2000
Change in cross sectional flow area
Disks (centrifugal stress)also called ‘Blisks’
Blades are twisted
Intra-Blade Supports
10
EXTREME TWIST: GE7000
11
AXIAL COMPRESSOR: SCHEMATIC REPRESENTATION
Centerline
Centerline
12
SCHEMATIC REPRESENTATION
13
AXIAL COMPRESSOR EXPLODED VIEW
14
HOW BLADES ARE ATTACHED
15
REVIEW: PRESSURE DISTRIBUTION• Rotor
– Adds swirl to flow
– Adds kinetic energy to flow with ½v2
– Increases total energy carried in flow by increasing angular momentum
• Stator
– Removes swirl from flow
– Not a moving blade → cannot add any net energy to flow
– Converts kinetic energy associated with swirl to internal energy by raising static pressure of flow
– NGV adds no energy. Adds swirl in direction of rotor motion to lower Mach number of flow relative to rotor blades (improves aerodynamics)
16
AXIAL COMPRESSOR ENERGY EXCHANGE• Rotor
– Adds swirl to flow
– Adds kinetic energy to flow with ½v2
– Increases total energy carried in flow by increasing angular momentum
• Stator
– Removes swirl from flow
– Not a moving blade → cannot add any net energy to flow
– Converts kinetic energy associated with swirl to internal energy by raising static pressure of flow
– NGV adds no energy. Adds swirl in direction of rotor motion to lower Mach number of flow relative to rotor blades (improves aerodynamics)
CenterlineN
GV R S R
17
COMPRESSOR AND FAN DATA FOR VARIOUS ENGINES
18
EXAMPLES OF BLADE TWIST
19
COMPRESSOR MAP
20
BOUNDARY LAYER LOSSES AND SEPARATION
21
LOSSES AND CASCADE TESTING
Measure of loss correlated toBlade geometry andEasily measured in cascade
22
SHOCK AND HIGH SPEED LOSSES
23
ENGINE TESTING: BIRD STRIKE
http://100.rolls-royce.com/facts/view.jsp?id=215
24
ADDITIONAL ISSUES AND BLADE TESTING
• Other Issues
– High Cycle Fatigue
– Materials
– Manufacturing
– Containment of Blade
– Disk Rupture
– Sealing
– Tip and Hub Losses
– Turbine Cooling Bleed
– Inspection
– Replacement Parts ($) ‘Blade-Out’ Simulation