Compressor Surge in IC Engines - ETH Z · Compressor • Reciprocating • Centrifugal • Axial...
Transcript of Compressor Surge in IC Engines - ETH Z · Compressor • Reciprocating • Centrifugal • Axial...
Compressor Surgein IC Engines
Compressor
• Reciprocating
• Centrifugal
• Axial
• Turbojet engines
• Power generation
• IC Engines
• Process industries
Various application areas and types:
[Source:http://www.turbobygarrett.com]
Operating range is limited
Compressor
PressureRatio
Mass flow
surge limit
Compressor Surge
1. Too high pressure risefor a certain massflow
Compressor Surge
2. Flow disruption, gas tends torevert (deep surge)
Compressor Surge
3. Pressure risedecreases
Compressor Surge
Limit cycles in the compressor characteristic
4. Flow reestablish itself
Moore-Greitzer Model
Compressor characteristicfor areas beyond stable region
෩Π𝑐( ሶ𝜇𝑐)
ሶ𝜇𝑡
ΠcΠc
ሶ𝜇𝑐
Throttle equation
Moore-Greitzer Model
Moore-Greitzer Simulation Tool
Download this tool from the course page.
Can we measure Compressor Surge?
pressure after compressorin bar
throttle position in %
TC speed in krpm
Compressor
Turbine
Throttle Intake
Exhaust
Reasons of Surge in IC Engines
1. Load steps: Full load -> Zero load– Displayed in Movie
Compressor
Turbine
Throttle Intake
Exhaust
Throttleopen
Throttleclosed
𝑝
𝑡
1. Load steps: Full load -> Zero load
2. Poorly designed compressor/turbinecomponents
Reasons of Surge in IC Engines
Turbinetoo small
Compressor map
Why operating the compressor near surge line?
• Minimize Turbo lag
– Reach desired boost pressure with the lowest possible compressor speed
• Maximize Low End Torque
– Get highest possible boost pressure for a certain compressor massflow
Desired boostpressure
Compressor
Turbine
Throttle Intake
Exhaust
Control Systems
Blow Off Valve
Diverter Valve
Waste Gate
Variable Turbine Geometry
Natural Gas port injection
Dieseldirect injection
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