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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 CEFRC Summer School, Copyright T. Lieuwen, 2012 2 Course Outline • Introduction – Constraints, metrics, future outlook • Flashback and Flameholding • Flame Stabilization and Blowoff • Combustion Instabilities • Flame Dynamics CEFRC Summer School, Copyright T. Lieuwen, 2012 3 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 CEFRC Summer School, Copyright T. Lieuwen, 2012 4 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 CEFRC Summer School, Copyright T. Lieuwen, 2012 5 Tradeoffs and Challenges Cost/ Turndown Complexity Combustion Blowoff Instabilities Emissions NO , CO, CO X 2 CEFRC Summer School, Copyright T. Lieuwen, 2012 6 Alternative Fuel Compositions • Source: L. Witherspoon and A. Pocengal, Power Engineering October 2008 7 Natural Gas Composition Variability Source: C. Carson, Rolls Royce Canada CEFRC Summer School, Copyright T. Lieuwen, 2012 8 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. CEFRC Summer School, Copyright T. Lieuwen, 2012 9 CEFRC Summer School, Copyright T. Lieuwen, 2012 10