Micro-combustion is the sequence of exothermic chemical reaction between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species at micro level. The release of heat can result in the production of light in the form of either glowing or a flame. Fuels of interest often include organic compounds (especially hydrocarbons) in the gas, liquid or solid phase. The major problem of micro-combustion is the high surface to volume ratio. As the surface to volume ratio increases heat loss to walls of combustor increases which leads to flame quenching.
The development of miniaturized products such as microrobots, notebook computers, micro-aerial vehicles and other small scale devices is becoming increasingly important in our daily life. There is a growing interest in developing small scale combustors to power these micro-devices due to their inherent advantages of higher energy density, higher heat and mass transfer coefficients and shorter recharge times compared to electrochemical batteries. The energy density of hydrocarbon fuels is 20-50 times higher than the most advanced Li-ion concept based electrochemical batteries. The concept of the micro-heat engine was proposed by Epstein and Senturia in 1997. Since then, substantial amount of work has been done towards the development and application of such small scale devices to generate power through the combustion of hydrocarbon fuels. Micro-combustors are an attractive alternate to batteries as they have large surface area to volume ratio, due to which, signiﬁcant amount of heat is transferred through the walls which leads to flame quenching. However, the increased rate of heat transfer through solid walls is advantageous in the case of steam reformers used for hydrogen production.
B. Khandelwal et al. have experimentally studied the flame stability limits and other characteristics in a two staged micro combustor. They found out that staged combustor leads to higher flame stability limits, in addition to that they also offer higher temperature profiles which would be helpful in utilizing the heat produced by combustion. Maruta et al. have experimentally studied the ﬂame propagation characteristics of premixed methane air mixtures in a 2.0 mm diameter straight quartz channel with a positive wall temperature gradient along the ﬂow direction. This was a simple one-dimensional conﬁguration to study flame stabilization characteristics in microchannels. Other researchers have studied the ﬂame stabilization behavior and combustion performance in a Swiss roll combustor, micro-gas turbine engines, a micro-thermo-photovoltaic system, a free piston knock engine, a micro-tube combustor, radial channel combustors, and in various other types of micro-combustor.
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- Kim, Nam Il; Kato, Souichiro; Kataoka, Takuya; Yokomori, Takeshi; Maruyama, Shigenao; Fujimori, Toshiro; Maruta, Kaoru (May 2005). "Flame stabilization and emission of small swiss-roll combustors as heaters". Combustion and Flame. 141 (3): 229–240. doi:10.1016/j.combustflame.2005.01.006. (subscription required (. ))
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- Khandelwal, Bhupendra; Sahota, Gur Partap Singh; Kumar, Sudarshan (August 27, 2010). "Investigations into the flame stability limits in a backward step micro scale combustor with premixed methane–air mixtures". Journal of Micromechanics and Microengineering. 20 (9). doi:10.1088/0960-1317/20/9/095030. (subscription required (. ))
- Maruta, K.; Kataoka, T.; Kim, N.I.; Minaev, S.; Fursenko, R. (January 2005). "Characteristics of combustion in a narrow channel with a temperature gradient". Proceedings of The Combustion Institute. 30 (2): 2429–2436. doi:10.1016/j.proci.2004.08.245. (subscription required (. ))
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- Shih, Hsin-Yi; Huang, Yen-Chin (June 2009). "Thermal design and model analysis of the swiss-roll recuperator for an innovative micro gas turbine". Applied Thermal Engineering. 29 (8-9): 1493–1499. doi:10.1016/j.applthermaleng.2008.06.029. (subscription required (. ))
- Yang, W.M.; Chou, S.K.; Shu, C.; Xue, H.; Lil, Z.W. (March 17, 2004). "Development of a prototype micro-thermophotovoltaic power generator". Journal of Physics D: Applied Physics. 37 (7): 1017–1020. doi:10.1088/0022-3727/37/7/011. (subscription required (. ))
- Aichlmayr, H.T.; Kittelson, D.B.; Zachariah, M.R. (November 2003). "Micro-HCCI combustion: experimental characterization and development of a detailed chemical kinetic model with coupled piston motion". Combustion and Flame. 135 (3): 227–248. doi:10.1016/S0010-2180(03)00161-5. (subscription required (. ))
- Li, Junwei; Zhong, Beijing (May 2008). "Experimental investigation on heat loss and combustion in methane/oxygen micro-tube combustor". Applied Thermal Engineering. 28 (7): 707–716. doi:10.1016/j.applthermaleng.2007.06.001. (subscription required (. ))
- Kumar, Sudarshan; Maruta, Kaoru; Minaev, S. (April 3, 2007). "Experimental investigations on the combustion behavior of methane-air mixtures in a new micro scale radial combustor conﬁguration". Journal of Micromechanics and Microengineering. 17 (5): 900. doi:10.1088/0960-1317/17/5/008. (subscription required (. ))
- Kumar, S.; Minaev, S.; Maruta, S.K. (January 2007). "On the formation of multiple rotating pelton-like ﬂame structures in radial microchannels with lean methane-air mixtures". Proceedings of The Combustion Institute. 31 (2): 3261–3268. doi:10.1016/j.proci.2006.07.174. (subscription required (. ))
- Khandelwal, Bhupendra; Kumar, Sudarshan (December 2010). "Experimental investigations on ﬂame stabilization behavior in a diverging micro channel with premixed methane-air mixtures". Applied Thermal Engineering. 30 (17-18): 2718–2723. doi:10.1016/j.applthermaleng.2010.07.023. (subscription required (. ))