On Heat Transfer of a Two-Step Radiating Slab of Variable Thermal Conductivity

Abstract:

An investigation of heat transfers in a combustible stockpile whose materials are of variable thermal conductivity is conducted in this article. The stockpile is modeled in rectangular slap and a two-step exothermic chemical reaction responsible for the combustion process is assumed. The reactive slab is also assumed to lose heat to the ambient by radiation. The Runge-Kutta Fehlberg (RKF45) method coupled with the Shooting technique is applied to tackle numerically the nonlinear ordinary differential equation (ODE) governing the problem. The process of heat transfer during combustion is made easy to understand by investigating effects of selected thermo-physical parameters on the system’s temperature. The results show that some thermo-physical parameters accelerate the exothermic chemical reaction and therefore raise the temperature levels, and that others help to reduce heat release rate to lower the temperature profiles. The graphs for the results are plotted and discussed accordingly.

• Periodical: Materials Science Forum (Volume 987)
• Pages: 137-141
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.987.137
• Online since: April 2020
• Authors: Ramoshweu Solomon Lebelo*
• Keywords: Exothermic Chemical Reaction, Heat Transfer, Numerical Methods, Two-Step Radiating Slab, Variable Thermal Conductivity

References

[1] O. D. Makinde, M. S. Tshehla, Analysis of thermal stability in a convecting and radiating twostep reactive slab, Adv. Mech. Eng. (2013) 1-9.

DOI: 10.1155/2013/294961

[2] R. S. Lebelo, R. K. Mahlobo, K. C. Moloi, Thermal stability analysis in a two-step reactive cylindrical stockpile, AJAS 15(2) (2018) 124-131.

DOI: 10.3844/ajassp.2018.124.131

[3] R. S. Lebelo, K. C. Moloi, K. O. Okosun, M. Mukamuri, S. O. Adesanya, M. S. Muthuvalu, Two-step low-temperature oxidation for thermal stability analysis of a combustible sphere, AEJ 57 (2018) 2829-2835.

DOI: 10.1016/j.aej.2018.01.006

[4] R. S. Lebelo, O. D. Makinde, T. Chinyoka, Thermal decomposition analysis in a sphere of combustible materials, Adv. Mech. Eng. 9(2) (2017) 1-14.

DOI: 10.1177/1687814017692515

[5] R. S. Lebelo, Thermal stability investigation in a reactive sphere of combustible material, Adv. Math. Phys. (2016) 1-9.

[6] E. R. Monazam, L. J. Shadle, A. Shamsi, Spontaneous combustion of char stockpiles, Energy & Fuels, 12 (1998) 1305-1312.

DOI: 10.1021/ef980094m

[7] D. A. Frank-Kamenetskii, Diffusion and heat transfer in chemical kinetics, Plenum Press, New York, (1969).

[8] O. D. Makinde, T. Chinyoka, R. S. Lebelo, Numerical investigation into CO2 emission, O2 depletion and thermal decomposition in a reacting slab, Math. Prob. Eng. (2011) 1-19.

DOI: 10.1155/2011/208426

[9] G. Nyamadzawo, W. Gwenzi, A. Kanda1, A. Kundhlande, C. Masona C, Understanding the Causes, Socio-economic and Environmental Impacts, and Management of Veld Fires in Tropical Zimbabwe, Fire Sci. Rev. 2(2) (2013) 1-13.

DOI: 10.1186/2193-0414-2-2

[10] B. H. Hamza, E. S. Massawe, O. D. Makinde, Analysis of transient heating due to exothermic reaction in a stockpile of combustible material, Int. J. Phys. Sci. 6(18) (2011) 4337-4341.

[11] J. M. Simmie, Detailed chemical kinetic model for the combustion of hydrocarbon fuels, Prog. Energy Combust. Sci. 29 (2003) 599-634.

DOI: 10.1016/s0360-1285(03)00060-1

[12] M. A. Sadiq, J. H. Merkin, Combustion in a porous material with reactant consumption: the role of the ambient temperature, Math Comput. Model, 20 (1994) 27-46.

DOI: 10.1016/0895-7177(94)90217-8

[13] S. Liao, J. Su, A. T. Chwang, Series solutions for a nonlinear model of combined convective and radiative cooling of a spherical body, Int. J. Heat. Mass. Tran. 49 (2006) 243-245.

DOI: 10.1016/j.ijheatmasstransfer.2006.01.030