A numerical study of steady diffusion flames established over ethanol fed porous spheres

• Autorzy: Vaibhav Kumar Sahu Vaibhav Kumar , Vasudevan Raghavan Vasudevan
• Języki publikacji: EN

Abstrakty

EN

An investigation of steady burning of liquid ethanol at the surface of porous spheres subjected to forced convective air flow has been carried out in this study. In this study, the diameter of the porous sphere is kept constant at 10 mm. Gasphase combustion at atmospheric pressure and under normal gravity has been studied numerically. A numerical model, which employs variable thermo-physical properties, a global single-step reaction mechanism and an optically thin radiation model, has been first validated against the published experimental results obtained from porous sphere technique. The validated model has been employed to study the effect of air velocity on flame behavior. Numerical results in terms of burning rates and velocity profiles around the sphere are presented. The flame zone in the front portion of the sphere (front stagnation point), where fresh air is supplied, becomes unstable as the air velocity is increased. This has been analyzed using the quantities such as oxygen contours and the momentum ratio.

Słowa kluczowe

EN

ethanol; porous sphere combustion; burning rate; single-step reaction kinetics; momentum ratio

• Wydawca: Komitet Termodynamiki i Spalania PAN
• Czasopismo: Archivum Combustionis
• Rocznik: 2011
• Tom: Vol. 31 nr 4
• Strony: 211--222
• Opis fizyczny: Bibliogr. 20 poz., rys., tab.

Twórcy

autor

Vaibhav Kumar Sahu Vaibhav Kumar

autor

Vasudevan Raghavan Vasudevan

• Graduate student, Department of Mechanical Engineering IIT Madras, Chennai, India,

Bibliografia

• [1] Modesto, M., Zemp, R.J., Nebra, SA., Ethanol Production from Sugar Cane: Assessing the Possibilities of Improving Energy Efficiency through Exergetic Cost Analysis, "Heat Transfer Engineering", 2009, 30, pp. 272 - 281.
• [2] Spalding, D. B., The combustion of liquid fuels, "Proc. Combust. Inst.", 1953,4, pp. 847-864.
• [3] Godsave, G. A. E., Studies of the combustion of drops in a fuel spray burning of single drop of fuel, "Proc. Combust. Inst.", 1953,4, pp. 818-830.
• [4] Gollahalli, S. R., Brzustowski, T.A., Experimental studies on flame structure in the wake flame of a burning droplet, "Proceedings of Combustion Institute", 1973 Volume 14, Issue 1, pp. 1333-1344.
• [5] Wise, H., Lorell, J., Wood, B.J., The effects of chemical and physical parameters on the burning rate of a liquid droplet, "Proc. Combust. Inst. 1955,5, pp. 132-141.
• [6] Sami, H., Ogasawara, M., Study on the burning of a fuel drop in heated and pressurized air stream, "JSME. Bulletin" 1970, 13, pp. 395-404.
• [7] Parag, S., Ragbavan, V., Experimental investigation of burning rates of pure ethanol and ethanol blended fuels, "Combustion and Flame", 2009 Volume 156, Issue 5, pp. 997-1005.
• [8] Kumagai, S., Sakai, T., Okajima, S., Combustion of free fuel droplets in a freely falling chamber, "Proceedings of Combustion Institute", 1971 Volume 13, Issue 1, pp. 779-785.
• [9] Balakrishnan, P., Sundararajan, T., Natarajan, R. Combustion of a fuel droplet in a mixed convective environment, "Combustion Science and Technology", 2001 Volume 163, Issue 1, pp. 77-106.
• [10] Ragbavan, V., Babu, V., Sundararajan, T., Natarajan, R., Flame shapes and burning rates of spherical fuel particles in a mixed convective environment, "Int. J. Heat Mass Transfer", 2005 Volume 48, pp. 53545370.
• [11] Pope, D.N., Gogos, G., Numerical simulation of fuel droplet extinction due to forced convection, "Combustion and Flame", 2005 Volume 142, pp. 89-106.
• [12] Raghavan, V., Gogos, G., Babu, V., Sundararajan, T. Effect of gravity on methanol diffusion flames burning within a forced convective environment, "International Communications in Heat and Mass Transfer", 2006, 33, pp. 686-697.
• [13] Raghavan, V., Gogos, G., Babu, V., Sundararajan, T., Entropy generation during the quasi-steady burning of spherical fuel particles, "International Journal of Thermal Sciences", 2007, 46, pp. 589-604.
• [14] Li, J., Kazakov, A., Dryer, F.L, Ethanol pyrolysis experiments in a variable pressure flow reactor, "International Journal of Chemical Kinetics", 2001 Volume 133, pp. 859-867.
• [15] Marinov, N. M., A detailed chemical kinetic model for high temperature ethanol oxidation, "International Journal of Chemical Kinetics", 1999 Volume 31, pp. 183-220.
• [16] Norton, T. S., Dryer, F.L., An experimental and modeling study of ethanol oxidation kinetics in an atmospheric pressure flow reactor, "International Journal of Chemical Kinetics", 1992 Volume 24, pp. 319-344.
• [17] Kazakov, A., Conley, J., Dryer, EL., Detailed modeling of isolated ethanol droplet combustion under microgravity conditions. "Combustion and Flame", 2003 Volume 134, Issue 4, pp. 301-314.
• [18] Dubey, Rishi, Bhadraiah, Kamam and Raghavan, Vasudevan, On the Estimation and Validation of Global Single-Step Kinetics Parameters of Ethanol-Air Oxidation Using Diffusion Flame Extinction Data, Combustion Science and Technology, volume 183, issue 1, (2011) pp. 43-50.
• [19] Barlow, R.S., Karpetis, A.N., F.J.H. and J.Y. Chen, Scalar profiles and no formation in laminar opposed flow partially pre-mixed methane/air flames, "Combustion and Flames", 2001 Volume 127, Issue 3, pp. 2102-2118.
• [20] Seiser, R., Humer, S., Seshadri, K., Pucher, E., Experimental investigation of methanol and ethanol flames in non-uniform flows, "Proceedings of Combustion Institute", 2007, 31, pp. 1173-1180.