Demand for greater engine efficiency and thrust-to-weight ratio has driven the production of aircraft engines with higher core temperatures and pressures. Such engines operate at higher fuel-air ratios, resulting in the potential for significant heat release through the turbine if species, such as CO and HC, are emitted from the combustor in large quantities. This paper outlines the magnitude and potential for turbine heat release in current and future engines. The analysis suggests that high fuel-air ratio designs may have to consider changes to cooling strategies to accommodate secondary combustion. A characteristic time methodology is developed to evaluate the chemical and fluid mechanical conditions that lead to combustion within the turbine. Local species concentrations partly determine the potential for energy release. An energy release parameter, here defined as a maximum increase in total temperature ΔTt, is used to specify an upper limit on the magnitude of impact. The likelihood of such impacts is set by the convective, mixing, and chemical processes that determine the fate and transport of species through the turbine. Appropriately defined Damko¨hler numbers (Da)—the comparative ratio of a characteristic flow time τflow to a characteristic chemical time τchem—are employed to capture the macroscopic physical features controlling the flow-chemistry interactions that lead to heat release in the turbine.

1.
Sirignano
,
W. A.
, and
Liu
,
F.
,
1999
, “
Performance Increases for Gas-Turbine Engines Through Combustion Inside the Turbine
,”
J. Propul. Power
,
15
, pp.
111
118
.
2.
Godin, Th., Harvey, S., and Stouffs, P., 1997, “Chemically Reactive Flow of Hot Combustion Gases in an Aircraft Turbo-Jet Engine,” ASME Paper No. 97-GT-302.
3.
Kirk, D. R., Guenette, G. R., Lukachko, S. P., and Waitz, I. A., 2002, “Turbine Durability Impacts of High Fuel-Air Ratio Combustors, Part 2: Impact of Intra-Turbine Heat Release on Film-Cooled Surface Heat Transfer,” ASME Paper No. GT-2002-30182.
4.
Bowman, C. T., Hanson, R. K., Davidson, D. F., Gardiner, W. C., Jr., Lissianski, V., Smith, G. P., Golden, D. M., Frenklach, M., and Goldenberg, M., 1995, “GRI-Mech 2.11, http://www.me.berkeley.edu/gri_mech/.”
5.
Kee, R. J., Rupley, F. M., and Miller, J. A., 1991, “CHEMKIN-II: A FORTRAN Chemical Kinetics Package for the Analysis of Gas-Phase Chemical Kinetics,” SAND89-8009, Sandia National Laboratories, Livermore, CA.
6.
Fotache
,
C. G.
,
Wang
,
H.
, and
Law
,
C. K.
,
1999
, “
Ignition of Ethane, Propane, and Butane in Counterflow Jets of Cold Fuel Versus Hot Air Under Variable Pressures
,”
Combust. Flame
,
117
, pp.
777
794
.
7.
Gordon, S., and McBride, B. J., 1994, “Computer Program for Calculation of Complex Chemical Equilibrium Compositions and Applications I. Analysis,” NASA-RP-1311, NASA Glenn Research Center, Cleveland, OH.
8.
International Civil Aviation Organization, 1995, ICAO Engine Exhaust Emissions Data Bank, First Ed. With Addendums, ICAO Doc 9646-AN/943. Montreal, Canada.
9.
U.S. Environmental Protection Agency, 1992, “Procedures for Emission Inventory Preparation: Volume IV, Mobile Sources,” EPA420-R-92-009, Washington, DC.
10.
Wey, C. C., et al., 1998, “Engine Gaseous, Aerosol Precursor and Particulate at Simulated Flight Altitude Conditions,” NASA-TM-1998-208509, NASA Glenn Research Center, Cleveland, OH.
11.
Howard, R. P., et al., 1996, “Experimental Characterization of Gas Turbine Emissions at Simulated Flight Altitude Conditions,” AEDC-TR-96-3, Arnold Engineering Development Center, Arnold Air Force Base, TN.
12.
Sturgess, G. J., McKinney, R., and Morford, S., 1992, “Modification of Combustor Stoichiometry Distribution for Reduced NOx Emission from Aircraft Engines,” ASME Paper No. 92-GT-108.
13.
Heywood, J. B., and Mikus, T., 1973, “Parameters Controlling Nitric Oxide Emissions from Gas Turbine Combustors,” Paper 21, Presented at AGARD Propulsion & Energetics Panels 41st Meeting on Atmospheric Pollution by Aircraft Engines, London, England.
14.
Mikus
,
T.
, and
Heywood
,
J. B.
,
1971
, “
The Automotive Gas Turbine and Nitric Oxide Emissions
,”
Combust. Sci. Technol.
,
4
, pp.
149
158
.
15.
Fric
,
T. F.
,
1993
, “
Effects of Fuel-Air Unmixedness on NOx Emissions,” Journal of Propulsion and Power
,”
J. Propul. Power
,
9
(
5
), pp.
708
713
.
16.
Lukachko
,
S. P.
,
Waitz
,
I. A.
,
Miake-Lye
,
R. C.
,
Brown
,
R. C.
, and
Anderson
,
M. R.
,
1998
, “
Production of Sulfate Aerosol Precursors in the Turbine and Exhaust Nozzle of an Aircraft Engine
,”
J. Geophys. Res.
,
103
(
D13
), pp.
159
16
.
17.
Penner, J. E., Lister, D. H., Griggs, D. J., Dokken, D. J., and McFarland, M., eds., 1999, “Special Report on Aviation and the Global Atmosphere,” IPCC, WMO/UNEP, Cambridge University Press, Cambridge, UK.
18.
Harnett, J. P., 1985, “Mass Transfer Cooling,” Handbook of Heat Transfer Fundamentals, W. M. Rohsenow, J. P. Hartnett, E. N. Ganic, eds., McGraw-Hill, New York, Chap. 1.
19.
Rolls-Royce, plc., 1992, The Jet Engine, 4th Ed., Derby, England.
20.
Lakshminarayna, B., 1996, Fluid Dynamics and Heat Transfer of Turbomachinery, New York.
You do not currently have access to this content.