Browsing by Author "Bou-Ali, M. Mounir"
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Item Design of a Radiant Heat Capturing Device for Steel Mills(2021) López Pérez, Susana; Herrero López, Saioa; Ubieta Astigarraga, Eduardo; del Hoyo Arce, Itzal; Gómez de Arteche Botas, Mercedes; Iturralde Iñarga, Jon; Fernández de Arroiabe Txapartegi, Peru; Bou-Ali, M. Mounir; Unamuno Iriondo, Iñigo; Tecnalia Research & Innovation; SISTEMAS TÉRMICOS EFICIENTESThis paper approaches the energy transition towards decarbonization and lower primary energy use in the steel and glass industries through the exploitation of radiant waste heat. In contrast with exhaust gases heat recovery, radiant waste heat has typically not been used. This energy waste is found in energy intensive processes in which high temperatures are reached. For instance, in the steel making process, the cast steel is red hot and emits a considerable amount of radiant energy. In this paper the conceptual design of a radiant heat capturing device is presented. This device enables the recovery of currently unused energy while solving the radiative emission-related problems. The achieved design gets to an optimized solution regarding view factors and optical properties of the involved surfaces. In this research work, those factors are optimized to maximize the amount of heat recovered by the presented device. Simulation tools are used to test different designs and define the most appropriate solution for a given case.Item Influence of the contact angle on the wettability of horizontal-tube falling films in the droplet and jet flow modes(2018-06) Fernández de Arroiabe, Peru; Martinez-Urrutia, Asier; Peña, Xabier; Martinez-Agirre, Manex; Bou-Ali, M. Mounir; Tecnalia Research & Innovation; SISTEMAS TÉRMICOS EFICIENTESWettability has a key impact on the performance of LiBr-H2O horizontal-tube falling film absorbers working under typical operating conditions. Therefore, it is necessary to study the influence of the wettability properties on the film hydrodynamics and wetted area. This work analyses the influence of the contact angle (0° – 120°) on the transient film hydrodynamics and the wetted area in the droplet and jet flow modes (7 ≤ Re ≤ 53). The comparison between two-dimensional and three-dimensional models evidences that three-dimensional models are needed for incomplete wetting conditions. The influence of the contact angle on both the film hydrodynamics and wetted area is demonstrated using 3D unsteady CFD model. Furthermore, the results indicate that each Reynolds number has a maximum contact angle to wet the whole tube steadily. When the value of the contact angle is lower than this maximum value, the contact angle has not influence on the wetting ratio. In contrast, at higher values, the wetting ratio decreases as the contact angle increases.Item Radiant waste heat recovery from steelmaking and glass industry(2019-09-24) Iturralde, Jon; Gómez de Arteche, Mercedes; Aguirre, Patricio; Bárcena, Jorge; López, Susana; Ubieta, Eduardo; Fernandez Arroiabe, Peru; Bou-Ali, M. Mounir; Unamuno, Iñigo; SISTEMAS TÉRMICOS EFICIENTES; Tecnalia Research & Innovation; EXTREMATThis paper tackles the problem of industrial waste heat recovery through an unexploited heat transfer mechanism: thermal radiation. Energy intensive industries have a considerable potential of unused radiant heat, which cannot be recovered through existing methods. That potential energy is quantified for the main identified industries: steel and glassmaking. Then, a radiant heat capturing device allowing high temperature heat capture is designed according to process requirements. Finally, recoverable heat is estimated and potential uses are proposed.