Hostname: page-component-8448b6f56d-qsmjn Total loading time: 0 Render date: 2024-04-24T07:59:21.810Z Has data issue: false hasContentIssue false
  • English
  • Français

Ignition in the supersonic hydrogen/air mixing layer with reduced reaction mechanisms

Published online by Cambridge University Press:  26 April 2006

H. G. Im ,
B. T. Helenbrook ,
S. R. Lee  and
C. K. Law
H. G. Im
Affiliation:
Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
B. T. Helenbrook
Affiliation:
Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
S. R. Lee
Affiliation:
Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
C. K. Law
Affiliation:
Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
Get access Rights & Permissions [Opens in a new window]

Abstract

Asymptotic analysis of ignition within the supersonic hydrogen/air mixing layer is performed using reduced mechanisms. Two distinct reduced mechanisms for the high-temperature and the low-temperature regimes are used depending on the characteristic temperature of the reaction zone relative to the crossover temperature at which the reaction rates of the H + 02 branching and termination steps are equal. Each regime further requires two distinct analyses for the hot-stream and the viscous-heating cases, depending on the relative dominance of external and internal ignition energy sources. These four cases are analysed separately, and it is shown that the present analysis successfully describes the ignition process by exhibiting turning point or thermal runaway behaviour in the low-temperature regime, and radical branching followed by thermal runaway in the high-temperature regime. Results for the predicted ignition distances are then mapped out over the entire range of the parameters, showing consistent behaviour with the previous one-step model analysis. Furthermore, it is demonstrated that ignition in the low-temperature regime is controlled by a larger activation energy process, so that the ignition distance is more sensitive to its characteristic temperature than that in the high-temperature regime. The ignition distance is also found to vary non-monotonically with the system pressure in the manner of the well-known hydrogen/oxygen explosion limits, thereby further substantiating the importance of chemical chain mechanisms in this class of chemically reacting boundary layer flows.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 322 , 10 September 1996 , pp. 275 - 296
Copyright
© 1996 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Abramowitz, M. & Stegun, A. 1965 Handbook of Mathematical Functions, pp. 686–697.
Egolfopoulos, F. N. & Law, C. K. 1990 Chain mechanisms in the overall reaction orders in laminar flame propagation. Combust. Flame 80, 7.Google Scholar
Figueira Da Silva, L. F., Desmans, B., Champion, M. & Rene-Corail, M. 1993 Some specific aspects of combustion in supersonic H2-air laminar mixing layers. Combust. Sci. Tech. 89, 317.Google Scholar
Grosch, C. E. & Jackson, T. L. 1991 Ignition and structure of a laminar diffusion flame in a compressible mixing layer with finite rate chemistry.. Phys. Fluids A 3, 3087.Google Scholar
Im, H. G., Bechtold, J. K. & Law, C. K. 1993 Analysis of thermal ignition in supersonic flat-plate boundary layers. J. Fluid Mech. 249, 99.Google Scholar
Im, H. G., Chao, B. H., Bechtold, J. K. & Law, C. K. 1994 Analysis of thermal ignition in the supersonic mixing layer. AIAA J. 32, 341.Google Scholar
Jackson, T. L. & Hussaini, M. Y. 1988 An asymptotic analysis of supersonic reacting mixing layers. Combust. Sci. Tech. 57, 129.Google Scholar
Klemp, J. B. & Acrivos, A. 1972 A note on the laminar mixing of two uniform parallel semi-infinite streams. J. Fluid Mech. 55, 25.Google Scholar
Kreutz, T. G. & Law, C. K. 1996 Ignition in nonpremixed counterflowing hydrogen versus heated air: computational study with detailed chemistry. Combustion Flame 104, 157.Google Scholar
Lee, S. R. & Law, C. K. 1994 Asymptotic analysis of ignition in nonpremixed counterflowing hydrogen versus heated air. Combust. Sci. Tech. 97, 377.Google Scholar
Lewis, B. & Elbe, G. Vo. 1987 Combustion, Flames and Explosions of Gases, 3rd edn. Academic.
Lock, R. C. 1951 The velocity distribution in the laminar boundary layer between parallel streams. Q. J. Mech. Appl. Maths 4, 42.Google Scholar
Marble, F. E. & Adamson, T. C. 1954 Ignition and combustion in a laminar mixing zone. Jet Propulsion 24, 85.Google Scholar
Nishioka, M. & Law, C. K. 1995 A numerical study of ignition in the supersonic hydrogen/air laminar mixing layer. AIAA Paper 95-0377.
Sanchez, A. L., Linan, A. & Williams, F. A. 1994 A bifurcation analysis of high temperature hydrogen oxygen ignition Twenty-Fifth Symp. (Intl) on Combustion, pp. 1529–1537. The Combustion Institute, Pittsburgh.
Skinner, G. B. & Ringrose, G. H. 1965 Ignition delays of a hydrogen-oxygen-argon mixture at relatively low temperatures. J. Chem. Phys. 42, 2190.Google Scholar
Treviño, C. 1991 Ignition phenomena in H2-O2 mixtures. In Dynamics of Deflagrations and Reactive Systems: Flames, (ed. A. L. Kuhl, J. C. Leyer, A. A. Borisov & W. A. Sirignano). Progress in Astronautics and Aeronautics, vol. 131, pp. 19–43. AIAA.
Treviño, C. & Mendez, F. 1991 Asymptotic analysis of the ignition of hydrogen by a hot plate in a boundary layer flow. Combust. Sci. Tech. 78, 197.Google Scholar