Heat loss analysis in a radiating slab of variable thermal conductivity

  • Authors

    • Ramoshweu S. Lebelo
    • Kholeka C. Moloi
    2018-04-20
    https://doi.org/10.14419/ijet.v7i2.23.11924
  • Heat Transfer, Numerical Methods, Radiation, Reactive Slab, Variable Thermal Conductivity.

  • This article investigates the transfer of heat in a stockpile of reactive materials, that is assumed to lose heat to the environment by radiation. The study is modeled in a rectangular slab whose materials are of variable thermal conductivity. The stockpile’s reactive material in this context is one that readily reacts with the oxygen trapped within the stockpile due to exothermic chemical reaction. The study of the combustion process in this case is conducted theoretically by using the Mathematical approach. The differential equation governing the problem is tackled numerically by applying the Runge-Kutta Fehlberg (RKF45) method coupled with the Shooting technique. To investigate the heat transfer phenomena, some kinetic parameters embedded in the governing differential equation, are varied to observe the behavior of the temperature profiles during the combustion process. The results obtained from the temperature profiles, are depicted graphically and discussed accordingly. It was discovered that kinetic phenomena such as the reaction rate parameter, accelerates the exothermic chemical reaction. However, the radiation parameter decelerates the exothermic chemical reaction by lowering the temperature profiles.

     

     

  • References

    1. [1] Lebelo RS (2016), Thermal stability investigation in a reactive sphere of combustible material. Advances in Mathematical Physics 2016, 1 – 9.

      [2] Monazam ER, Shadle LJ & Shamsi A (1998), Spontaneous combustion of char stockpiles. Energy & Fuels 12, 1305-1312.

      [3] Kaji R, Hishinuma Y & Nakamura Y (1985), Low temperature oxidation of coals. Effects of pore structure and coal composition. Fuel 64, 297-302.

      [4] Quick JC & Glick DC (2000), Carbon dioxide from coal combustion: variation with rank of US coal. Fuel 79(7), 803–812.

      [5] Makinde OD, Chinyoka T & Lebelo RS (2011), Numerical investigation into CO2 emission, O2 depletion and thermal decomposition in a reacting slab. Mathematical Problems in Engineering 2011, 1 – 19.

      [6] Unal S (1995), A review of spontaneous combustion of coals. Fuel Science and Technology International 13(9), 1995, 1103-1120.

      [7] Lohrer C, Krause U & Steinbach J (2005), Self-ignition of combustible bulk materials under various ambient conditions. Process Safety and Environmental Protection 8, 145–150.

      [8] Hensel W, Krause U & Loffler U (2004), Self-ignition of materials (including dust). In: Hartwig M and Steen H (eds) Handbook of explosion prevention and protection. Weinheim: Wiley-VCH 2.7, 227–270.

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

      [10] Lebelo RS, Mahlobo RK, Adesanya SO & Muthuvalu MS, “On Heat Transfer Analysis for a Sphere of Combustible Material of

      Variable Thermal Conductivity†IOP Conference Series: Materials Science and Engineering, 269, 2017, 1 – 6,

      http://dx doi:10.1088/1757-899X/269/1/012062.

      [11] Lebelo RS (2017), Thermal conductivity impact on thermal stability of reactive materials. Diffusion Foundations 11, 1-10.

      [12] Makinde OD (2012), Hermite–Pade_ approach to thermal stability of reacting masses in a slab with asymmetric convective cooling. Journal of Franklin Institute 349, 957 – 965.

      [13] Hamza BH, Massawe ES & Makinde OD (2011), Analysis of transient heating due to exothermic reaction in a stockpile of combustible material. International Journal of Physical Sciences 6(18), No 18, 4337 – 4341.

      [14] Legodi AMK & Makinde OD (2011), A numerical study of steady state exothermic reaction in a slab with convective boundary conditions. International Journal of the Physical Sciences 6(10), 2541-2549.

      [15] Lebelo RS & Makinde OD (2015), Modelling the impact of radiative heat loss on CO2 emission, O2 depletion and thermal stability in a seactive Slab. IJST, Transactions of Mechanical Engineering 39(M2), 351-365.

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  • How to Cite

    S. Lebelo, R., & C. Moloi, K. (2018). Heat loss analysis in a radiating slab of variable thermal conductivity. International Journal of Engineering & Technology, 7(2.23), 228-231. https://doi.org/10.14419/ijet.v7i2.23.11924