Abstract
A series of experiments were performed to elucidate the influence of residence time of fuel vapor transport on the sooting behavior of microgravity ethanol droplet flames using the 2.2 sec drop-tower facilities at the NASA Glenn Research Center (GRC). In these experiments, the residence time of fuel vapor transport was adjusted by means of changes in initial droplet diameters (1.6 mm versus 1.9 mm) and oxygen concentrations (ranging from 21 % to 33 % mole fraction in argon atmospheric environments). As the flame temperature is increased, the measured soot volume fraction initially increased and then began to decrease after reaching a maximum value. Experimental results clearly indicate that the residence time can control the sooting behavior for microgravity droplet flames by mediating the competition among the fuel pyrolysis reactions, fragmentation of formed soot precursors, and oxidation of soot precursors and particles which eventually result in an interesting non-monotonic sooting behavior at elevated flame temperatures.
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Bundy, M., Hamins, A., Lee, K.Y.: Suppression limits of low strain rate non-premixed methane flames. Combust.Flame 133, 299–310 (2003)
Dasch, C.J.: One-dimensional tomography: A comparison of Abel, onionpeeling, and filtered back projection methods. Appl. Opt. 31, 1146–1152 (1996)
Frenklach, M., Clary, D.W., Gardiner, W.C., Stein. S.E.: Detailed kinetic modeling of soot formation in shock-tube pyrolysis of acetylene. Proc. Combust. Inst. 20, 887–901 (1984)
Glassman, I.: Sooting laminar diffusion flames: Effect of dilution, additives, pressure, and microgravity. Proc. Combust. Inst. 27, 1589–1596 (1998)
Glassman, I.: Combustion. Academic Press, Orlando (1995)
Gulder, O.L., Snelling, D.R.: Influence of nitrogen dilution and flame temperature on soot formation in diffusion. flames. Combust. Flame 92, 115–124 (1993)
Guo, H., Liu, F., Smallwood, G.J., Gulder, O.L.: Inter. J. Comput. Fluid Dynam. 18(2), 139–151 (2004)
Hara, H., Kumagai, S.: Experimental investigation of free droplet combustion under microgravity. Proc. Combust. Inst. 23, 1605–1610 (1991)
Jackson, G.S., Avedisian, C.T., Yang, J.C.: Observations of soot during droplet combustion at low gravity: Heptane and heptane/monochloroalkane mixtures. Int. J. Heat Mass Trans. 35, 2017–2033 (1992)
Kazakov, A., Conley, J., Dryer, F.L.: Detailed modeling of an isolated, ethanol droplet combustion under microgravity conditions. Combust. Flame 134, 301–314 (2003)
Kitamura, T., Ito, T., Senda, J., Fujimoto, H.: Extraction of the suppression effects of oxygenated fuels on soot formation using a detailed chemical kinetic model. JSAE Rev. 22, 139–145 (2001)
Koylu, U.O., Faeth, G.M.: Carbon-monoxide and soot emissions from liquid-fueled buoyant turbulent-diffusion flames. Combust. Flame 87, 61–76 (1991)
Lee, K.O., Choi, M.Y.: Observations on the sooting behavior of microgravity droplet flames under reduced pressures. Microgravity Sci. Technol. X/2, 86–94 (1997)
Lee, K.O., Manzello, S.L., Choi, M.Y.: The effects of initial droplet diameter on sooting and burning behavior of isolated droplets under microgravity conditions. Combust. Sci. and Tech. 132, 139–156 (1998)
Marchese, M.A., Dryer, F.L.: The effect of non-luminous thermal radiation in microgravity droplet combustion. Combust. Sci. Technol. 124, 371–402 (1997)
Okajima, S., Kumagai, S.: Further investigations of combustion of free droplets in a freely falling chamber including moving droplets. Proc. Combust. Inst. 15, 401–407 (1975)
Park, S.H., Choi, S.C., Choi, M.Y., Yozgatligil, A.: New observations of isolated ethanol droplet flames in microgravity conditions. Combust. Sci. Technol. 180(4), 631–651 (2008)
Richter, H., Howard, H., Richter, J.B.: Formation of polycyclic aromatic hydrocarbons and their growth to soot—a review of chemical reaction pathways. Prog. Energy Combust. Sci. 26, 565–608 (2000)
Vilimpoc, V., Goss, L.: SiC-based thin-filament pyrometry: Theory and thermal properties. Proc. Combust. Inst. 22, 1907–1914 (1989)
Yozgatligil, A., Park, S.H., Choi, M.Y., Kazakov, A., Dryer, F.L.: Burning and sooting behavior of ethanol droplet combustion under microgravity condition. Combust. Sci. Tech. 176, 1–15 (2004)
Yozgatligil, A., Park, S.H., Choi, M.Y., Kazakov, A., Dryer, F.L.: Influence of oxygen concentration on the sooting behavior of ethanol droplet flames in microgravity conditions. Proc. Combust. Inst. 31, 2165–2173 (2007)
Acknowledgments
Support from NASA through Grant NCC3-822 is gratefully acknowledged. S.H. Park also would like to acknowledge the financial support from Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (2014R1A1A1002184).
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Park, SH., Choi, M.Y. Influences of Residence time of Fuel Vapor Transport on Sooting Behavior of Ethanol Droplet Flames in Microgravity. Microgravity Sci. Technol. 27, 337–344 (2015). https://doi.org/10.1007/s12217-015-9420-6
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DOI: https://doi.org/10.1007/s12217-015-9420-6