Internal Combustion Engines I: Gas Turbines

207 Pages·2012·8.92 MB·English

Internal Combustion Engines I:
Gas Turbines

Tim Lieuwen

Affiliation:
Professor
School of Aerospace Engineering
Georgia Institute of Technology
Email: [email protected]
Ph. 404-894-3041

2012 Princeton-CEFRC Summer School on Combustion
Course Length: 6 hrs
June 25 – 26, 2012
Course Outline
• Introduction
• Flashback and Flameholding
• Flame Stabilization and Blowoff
• Combustion Instabilities
• Flame Dynamics

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Course Outline
• Introduction
– Constraints, metrics, future outlook
• Flashback and Flameholding
• Flame Stabilization and Blowoff
• Combustion Instabilities
• Flame Dynamics

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Role of Combustor within Larger
Energy System
0.7
0.6
Microturbine
• Example: Ideal Brayton Cycle y
c 0.5
n
e Heavy Aeroengine
– = 1- (Pr)-( -1)/ iciffE 0.4 frame Gas
th la 0.3 Turbine
m
• Pr = compressor pressure ratio re 0.2
h
T
0.1
• = C /C , ratio of specific heats
p v
0
0 10 20 30 40
• Conclusions
Pressure Ratio
– Combustor has little effect upon cycle efficiency (e.g. fuel –> kilowatts) or
specific power
– Combustor does however have important impacts on
• Realizability of certain cycles
– E.g., steam addition, water addition, EGR, etc.
• Engine operational limits and transient response
• Emissions from plant
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Combustor Performance Metrics
• What are important combustor performance
parameters?
– Operability
Fuel
• Blow out
• Combustion instability
• Flash back
Air
• Autoignition
– Low pollutant emissions
– Fuel flexibility
– Good turndown
– Transient response

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Tradeoffs and Challenges

Cost/
Turndown
Complexity

Combustion
Blowoff
Instabilities

Emissions
NO , CO, CO
X 2
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Alternative Fuel Compositions
• Source: L.
Witherspoon and
A. Pocengal,
Power Engineering
October 2008
7
Natural Gas Composition Variability
Source: C. Carson, Rolls Royce Canada
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Operability issues have caused
significant problems in deployment of
low NO technologies
X
• Power
– Example: Broken part
replacement largest non-fuel
related cost for F class gas
turbines
• Industrial
• Residential
– Example: issues in EU with
deployment of low NO water
X
heaters, burners
Goy et al., in Combustion instabilities in gas turbine engines: operational
experience, fundamental mechanisms, and modeling,

T. Lieuwen and V. Yang, Editors. 2005. p. 163-175.
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