Thermo-Fluids Modelling of Ancient Iron Smelting Process of Sri Lanka

Abstract

Archealogical survays undertaken since 1988 at Samanalawawa, the hilly terrain between lowerland and centrel highlands of Sri Lanka, have revealed the evidences of an acient Iron Smelting technology that produced high quality high carbon steel. The winds in intermonsoon period (June-September) provided the energy requird by the fiimances in Smanalawawa Valley.The surveys further revealed that the iron thus produced contained 68.7% and 79.5% of ferric oxide which is equivalent to 45% and 55% of metallic iron respectively. This discovery became nationally important to Sri Lanka. In 1996, Tabor et al. (J. Arch Sci, 32(5), p.753) carried out an archeological survey and excavation project in Samanalawawa valley that led to a series of experimental iron-smelting field trials. They successfully reconstructed a late-1st millennium AD wind-powered furnace, and also did some preliminary modeling of wind patterns using the commercial Computational Fluid Dynamics (CFD) package of ANSYS. The inlet velocities were fixed at 0 km/h at ground level, 15 km/h af 0.5 m above ground level and 30 km/h at 2 m above ground level. The temperature within the furnace was set to 1200 °C. Further studies were required on thermo-flu ids in the furnace. This paper addresses those aspects. Here the open source software OpenFOAM was used in place of ANSYS for economy and versatility. The boundary conditions of air velocity, temperature and packed-bed porosity were applied and the modeling of combustion inside the furnace was examined. Next step is to develop a solver to analyze the burning of charcoal that would lead to the optimization of the combustion process and most efficient use of natural wind power in the iron smelting process.