Hostname: page-component-7479d7b7d-q6k6v Total loading time: 0 Render date: 2024-07-10T13:26:41.408Z Has data issue: false hasContentIssue false

Theoretical analysis of ultra-lean premixed flames in porous inert media

Published online by Cambridge University Press:  10 June 2010

F. M. PEREIRA*
Affiliation:
Departamento de Engenharia Mecânica, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil
A. A. M. OLIVEIRA
Affiliation:
Departamento de Engenharia Mecânica, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil
F. F. FACHINI
Affiliation:
Laboratório de Combustão e Propulsão, Instituto Nacional de Pesquisas Espaciais, 12630-000 Cachoeira Paulista, SP, Brazil
*
Email address for correspondence: fernando@labcet.ufsc.br

Abstract

The structure of stationary adiabatic premixed flames within porous inert media under intense interphase heat transfer is investigated using the asymptotic expansion method. For the pore sizes of interest for combustion in porous inert media, this condition is reached for extremely lean mixtures where lower flame velocities are found. The flame structure is analysed in three distinct regions. In the outer region (the solid-phase diffusion length scale), both phases are in local thermal equilibrium and the problem formulation is reduced to the one-equation model for the energy conservation. In the first inner region (the gas-phase diffusion length scale), there is local thermal non-equilibrium and two equations for the energy conservation are required. In this region, the gas-phase temperature at the flame is limited by the interphase heat transfer. In the second inner region (the reaction length scale), the chemical reaction occurs in a very thin zone where the highest gas-phase temperature is found. The results showed that superadiabatic effects are reduced for leaner mixtures, smaller pore sizes and smaller fuel Lewis numbers. The results also show that there is a minimum superadiabatic temperature for the flame propagation to be possible, which corresponds to the lean flammability limit for the premixed combustion in porous inert media. A parameter that universalizes the leading-order flame properties is identified and discussed.

Type
Papers
Copyright
Copyright © Cambridge University Press 2010

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

REFERENCES

Boshoff-Mostert, L. & Viljoen, H. J. 1996 Analysis of the homogeneous combustion in monolith structures. Chem. Engng Sci. 51, 11071111.CrossRefGoogle Scholar
Bubnovich, V. I., Zhdanok, S. A. & Dobrego, K. V. 2006 Analytical study of the combustion waves propagation under filtration of methane–air mixture in a packed bed. Intl J. Heat Mass Transfer 49, 25782586.CrossRefGoogle Scholar
Buckmaster, J. D. & Takeno, T. 1981 Blow-off and flashback of an excess-enthalpy flame. Combust. Sci. Technol. 25, 153159.CrossRefGoogle Scholar
Catapan, R. C., Pereira, F. M. & Oliveira, A. A. M. 2005 Development of a radiant porous burner with a combined thermal and fluidynamic mechanism of flame stabilization. In Proceedings of the International Congress of Mechanical Engineering: COBEM 2005 Ouro Preto, MG, Brazil.Google Scholar
Deshaies, B. & Joulin, G. 1980 Asymptotic study of an excess-enthalpy flame. Combust. Sci. Technol. 22, 281285.CrossRefGoogle Scholar
Dobrego, K. V., Gnesdilov, N. N., Lee, S. H. & Choi, H. K. 2008 Lean combustibility limit of methane in reciprocal flow filtration combustion reactor. Intl J. Heat Mass Transfer 51, 21902198.CrossRefGoogle Scholar
Echigo, R. 1991 Radiation enhanced/controlled phenomena of heat and mass transfer in porous media. ASME/JSME Therm. Engng Proc. 4, 2132.Google Scholar
Fachini, F. F. 1996 The effects of the acoustic field on droplet extinction processes. Combust. Sci. Technol 156, 237253.Google Scholar
Fachini, F. F. 2005 Large-activation-energy asymptotic analysis of multicomponent fuel diffusion flames. Combust. Sci. Technol. 177, 17931811.CrossRefGoogle Scholar
Fachini, F. F., Liñán, A. & Williams, F. A. 1999 Theory of flame histories in droplet combustion at small stoichiometric fuel-air ratios. AIAA J. 37, 14261435.CrossRefGoogle Scholar
Fu, X., Viskanta, R. & Gore, J. P. 1998 Measurement and correlation of volumetric heat transfer coefficients of cellular ceramics. Exp. Therm. Fluid Sci. 17, 285293.Google Scholar
Golombok, M., Prothero, A., Shirvill, L. C. & Small, L. M. 1991 Surface combustion in metal fibre burners. Combust. Sci. Techol. 77, 203223.CrossRefGoogle Scholar
Hackert, C. L., Ellzey, J. L. & Ezekoye, O. A. 1999 Combustion and heat transfer in model two-dimensional porous burners. Combust. Flame 116, 177191.CrossRefGoogle Scholar
Hardesty, D. R. & Weinberg, F. J. 1974 Burners producing large excess enthalpies. Combust. Sci. Technol. 8, 201214.CrossRefGoogle Scholar
Henneke, M. R. & Ellzey, J. 1999 Modeling of filtration combustion in a packed bed. Combust. Flame 117, 832840.CrossRefGoogle Scholar
Hoffmann, J. G., Echigo, R., Yoshida, H. & Tada, S. 1997 Experimental study on combustion in porous media with a reciprocating flow system. Combust. Flame 111, 3246.CrossRefGoogle Scholar
Howell, J. R., Hall, M. J. & Ellzey, J. L. 1996 Combustion of hydrocarbon fuels within porous inert media. Prog. Energy Combust. Sci. 22, 121145.CrossRefGoogle Scholar
Hsu, P., Evans, W. D. & Howell, J. R. 1993 Experimental and numerical study of premixed combustion within nonhomogeneous porous ceramics. Combust. Sci. Technol. 90, 149172.CrossRefGoogle Scholar
Kaviany, M. 1995 Principles of Heat Transfer in Porous Media, 2nd edn. Springer.CrossRefGoogle Scholar
Kaviany, M. 2001 Principles of Heat Transfer. Wiley.CrossRefGoogle Scholar
Kotani, Y., Behbahani, H. F. & Takeno, T. 1984 An excess enthalpy flame combustor for extended flow ranges. In Proceedings of 20th Symposium (Int.) on Combustion, pp. 2025–2033.Google Scholar
Kotani, Y. & Takeno, T. 1982 An experimental study on stability and combustion characteristics of an excess enthalpy flame. In Proceedings of 19th Symposium (Int.) on Combustion, pp. 1503–1509.Google Scholar
Law, C. K. 2006 Combustion Physics. Cambridge University Press.CrossRefGoogle Scholar
Liñán, A. 1974 The asymptotic structure of counterflow diffusion flames for large activation energies. Acta Astronaut. 1, 10071039.CrossRefGoogle Scholar
Liu, J. F. & Hsieh, W. H. 2004 Experimental investigation of combustion in porous heating burners. Combust. Flame 138, 295303.CrossRefGoogle Scholar
McIntosh, A. C. 1988 Simplified model of a surface-combustion burner with radiant heat emission. AIAA Prog. Astronaut. Aeronaut. 113, 385405.Google Scholar
McIntosh, A. C. & Prothero, A. 1991 A model of large heat transfer surface combustion with radiant heat emission. Combust. Flame 83, 111126.CrossRefGoogle Scholar
Min, D. K. & Shin, H. D. 1991 Laminar premixed flame stabilized inside a honeycomb ceramic. Intl J. Heat Mass Transfer 34, 341356.Google Scholar
Mößbauer, S., Pickenäcker, O., Pickenäcker, K. & Trimis, D. 1999 Application of the porous burner technology in energy- and heat-engineering. In Proceedings of the Fifth International Conference on Technologies and Combustion for a Clean Environment (Clean Air V), Lisbon, Portugal, vol. 1, pp. 519523.Google Scholar
Oliveira, A. A. M. & Kaviany, M. 2001 Nonequilibrium in the transport of heat and reactants in combustion in porous media. Prog. Energy Combust. Sci. 27, 523545.CrossRefGoogle Scholar
Pereira, F. M., Oliveira, A. A. M. & Fachini, F. F. 2009 Asymptotic analysis of stationary adiabatic premixed flames in porous inert media. Combust. Flame 156, 152165.CrossRefGoogle Scholar
Sahraoui, M. & Kaviany, M. 1994 Direct simulation vs. volume-averaged treatment of adiabatic, premixed flame in a porous medium. Intl J. Heat Mass Transfer 37, 28172834.CrossRefGoogle Scholar
Schoegl, I. & Ellzey, J. 2007 Superadiabatic combustion in conducting tubes and heat exchangers of finite length. Combust. Flame 151, 142159.CrossRefGoogle Scholar
Schultz, D. A., Matkowsky, B. J., Volker, V. A. & Fernandez-Pello, A. C. 1996 Forced forward smolder combustion. Combust. Flame 104, 126.CrossRefGoogle Scholar
Shi, J. R., Xie, M. Z., Liu, H., Li, G. & Zhou, L. 2008 Numerical simulation and theoretical analysis of premixed low-velocity filtration combustion. Intl J. Heat Mass Transfer 51, 18181829.CrossRefGoogle Scholar
Telengator, A. M., Williams, F. A. & Margolis, S. B. 2006 Finite-rate interphase heat transfer effects on multiphase burning in confined porous propellants. Combust. Sci Technol. 178, 16851720.CrossRefGoogle Scholar
Wahle, C. W. & Matkowsky, B. J. 2001 Rapid, upward buoyant filtration combustion waves driven by convection. Combust. Flame 124, 1434.CrossRefGoogle Scholar
Wahle, C. W., Matkowsky, B. J. & Aldushin, A. P. 2003 Effects of gas-solid nonequilibrium in filtration combustion. Combust. Sci. Technol. 175, 13891499.CrossRefGoogle Scholar
Williams, F. A. 1985 Combustion Theory: The Fundamental Theory of Chemically Reacting Flow Systems. Perseus Books.Google Scholar
Wood, S. & Harris, A. 2008 Porous burners for lean-burn applications. Prog. Energy Combust. Sci. 34, 667684.CrossRefGoogle Scholar
Zhdanok, S., Kennedy, L. A. & Koester, G. 1995 Superadiabatic combustion of methane air mixtures under filtration in a packed bed. Combust. Flame 100, 221231.CrossRefGoogle Scholar
Zhu, D. L., Egolfopoulos, F. N. & Law, C. K. 1989 Experimental and numerical determination of laminar flame speeds of methane/(Ar, N2, CO2)-air mixtures as function of stoichiometry, pressure and flame temperature. In Proceedings of 22nd Symposium (Int.) on Combustion, pp. 1539–1545.Google Scholar