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

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 efficiency of panela burners is 30% on average. Objective: The objective of this investigation is to contribute to the search for new alternatives for the improvement of the low efficiency present on these systems, mainly affecting the flue gases duct. Methodology: The development of this study is as follows: first, a research of the radiation and optical thickness effect in a simplified furnace is carried out. Afterward, 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 thickness 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 transferred 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 significant differences between the DOM and the P-1 radiation were found.Introducción: La panela es un producto derivado de la caña de azúcar. En su elaboración se utiliza una hornilla tradicional, diseñada especialmente para este propósito. Según estudios encontrados en la literatura, se ha identificado que la eficiencia térmica de las hornillas paneleras se estima en un 30% promedio. Objetivo: Esta investigación tiene como objetivo contribuir en la búsqueda de nuevas soluciones para el mejoramiento del nivel de eficiencia, modificando principalmente el ducto de humos. Metodología: El desarrollo de este estudio es el siguiente: primero, se realiza una investigación del efecto de la radiación y del espesor óptico en un horno simplificado. Posteriormente, se realiza una serie de simulaciones con modificaciones en el diseño del ducto de humos para un horno de tamaño real. Resultados: Los resultados mostraron que se debe considerar el efecto de la radiación. Aunque el espesor óptico sea bajo, tiene un impacto relevante en el proceso de transferencia de calor debido a las altas temperaturas en el horno. Un movimiento caótico de los gases implicó más calor transferido a las pailas, y se obtuvieron altos valores de Nusselt con la adición de nuevos elementos en el conducto. Conclusiones: El arreglo 1, proporciona los mejores resultados con un aumento de la eficiencia térmica y de Nusselt. No se encontraron diferencias significativas entre los modelos de radiación DOM y P-1

Analysis of flow channel insert deformations influence on the liquid metal flow in DCLL blanket channels

The dual coolant lithium lead (DCLL) is a candidate to be an effective breeding blanket (BB) concept for nuclear fusion technologies. One critical point of this design is the magnetohydrodynamic (MHD) effects involving Lorentz damping force which produces relevant pressure drop in the eutectic flow. In the framework of the European DEMO, the application of sandwich-like steel–alumina–steel flow channel insert (FCI) seems to be the best solution to reduce the pressure drop by electrically decoupling the liquid PbLi from the Eurofer walls. The impact of the FCI on the PbLi velocity profile is analyzed in this work with a CFD solver implemented on OpenFOAM. Under the assumption of non-buoyant fully developed channel flow the temperature map in the channel is computed. Based on the temperature field, the induced deformation is evaluated. The effects of the FCI deformation and possible rupture of the FCI on the velocity profile and on the corresponding pressure drop are then parametrically investigated. Results show that the deformation of the FCI and the possible break in the Hartmann wall do not lead to significant variations in the pressure drop from the case of intact FCI in a wide range of interaction parameters

MHD issues related to the use of Lithium Lead eutectic as breeder material for blankets of fusion power plants

The European Community is committed to the development of a DEMOnstration fusion power plant whose operation could start as soon as 2050. The blanket is one of the most critical components in a fusion reactor; three of the four blanket concepts currently under development are based on the use of the liquid eutectic alloy Pb-15.7Li. Since the blanket will operate under the strong magnetic field used to confine the plasma, electromagnetic forces will occur in the PbLi flow, giving rise to magnetohydrodynamic (MHD) phenomen