Numerical analysis of the thermal and fluid dynamic behavior of the flue gases in a traditional furnace for panela production

Abstract

Introduction−Panela is a product derived from sugar cane that is prepared using a traditional burner designed especially for this purpose. According to studies found in the literature, it was identified that the thermal ef-ficiency of panela burners is 30% on average.Objective−The objective of this investigation is to con-tribute to the search for new alternatives for the im-provement of the low efficiency present on these systems, mainly affecting the flue gases duct.Methodology−The development of this study is as fol-lows: first, a research of the radiation and optical thick-ness effect in a simplified furnace is carried out. After-ward, a series of simulations with modifications in the design of the flue gas duct for a real size furnace are analyzed.Results−The results showed that the radiation effect must be considered and, even though the optical thick-ness is low, it has a relevant impact in the heat transfer process due to the high temperatures in the furnace. A chaotic movement of the gases implied more heat trans-ferred to the heaters and high values of Nusselt with the addition of new elements in the duct were obtained.Conclusions−Arrangement 1, provides the best results with a Nusselt and thermal efficiency increase. No sig-nificant differences between the DOM and the P-1 radia-tion were found.

Keywords

• cfd
• turbulent flow
• radiation heat transfer
• industrial furnace