The laboratory scale ram combustor test program has been investigating fundamental combustion characteristics of a ram combustor, which operates from Mach 2.5 to 5 for the super/hypersonic transport propulsion system. In our previous study, combustion efficiency had been found poor, less than 70 percent, due to a low inlet air temperature and a high velocity at Mach 3 condition. To improve the low combustion efficiency, a fuel zoning combustion concept was investigated by using a subscale combustor model first. Combustion efficiency more than 90 percent was achieved and the concept was found very effective. Then a laboratory scale ram combustor was fabricated and combustion tests were carried out mainly at the simulated condition of Mach 5. A vitiation technique was used to simulate a high temperature of 1263 K. The test results indicate that ignition, flame stability, and combustion efficiency were not significant, but the NOx emissions are a critical problem for the ram combustor at Mach 5 condition.

Issue Section:
Gas Turbines: Aircraft
Topics:
Combustion chambers, Fuels, Methane, Combustion, Emissions, Flames, High temperature, Ignition, Nitrogen oxides, Propulsion systems, Stability, Temperature
1.
Branstetter, J. R., and Reck, G. M., 1973, “Afterburner Performance of Circular V-Gutters and a Sector of Parallel V-Gutters for a Range of Inlet Temperatures to 1255 K (1800°F),” NASA TN D-7212.
2.
Gregory, M. R., Robert, B., and Larry, A. D., 1971, “Preliminary Sector Tests at 920 K (1200°F) of Three Afterburner Concepts Applicable for Higher Inlet Temperatures,” NASA TN D-6437.
3.
Kinoshita, Y., Kitajima, J., Shiraha, M., and Tatara, A., 1992, “Combustion Study on Methane-Fuel Laboratory Scale Ram Combustor,” ASME Paper No. 92-GT-413.
4.
Kinoshita, Y., Kitajima, J., and Seki, Y., 1993, “Studies on Methane-Fuel Ram Combustor for HST Combined Cycle Engines,” Paper No. ISABE 93-7080.
5.
Longwell, J. P., 1953, “Flame Stabilization by Bluff Bodies and Turbulent Flames in Ducts,” Forth Symposium (International) on Combustion, The Williams and Wilkins Company, Baltimore, MD, pp. 90–97.
6.
Longwell
J. P.
,
Frost
E. E.
, and
Weiss
M. A.
,
1953
, “
Flame Stability in Bluff Body Recirculation Zones
,”
Industrial and Engineering Chemistry
, Vol.
45
, No.
8
, pp.
1629
–
1633
.
7.
Mullen
J. W.
, and
Fenn
J. B.
,
1951
, “
Burners for Supersonic Ram-jets: Factors Controlling Over-all Burner Performance
,”
Engineering and Process Development
, Vol.
43
, No.
1
, pp.
195
–
211
.
8.
Watanabe, Y., Miyagi, H., Sekido, T., Miyagawa, H., Tanaka, F., Aoki, T., Morita, M., and Yanagi, R., 1983, “Conceptual Design Study on Combined-Cycle Engine for Hypersonic Transport,” Paper No. ISABE 93-7018.
This content is only available via PDF.
Copyright © 1995
 by The American Society of Mechanical Engineers
You do not currently have access to this content.