Numerical simulation of twisted tapes fitted in circular tube consisting of alternate axes and regularly spaced tapes

• Autor(a) principal: Khalili Asboei, Alireza
• Data de Publicação: 2018
• Outros Autores: Vazifeshenas, Yousef, Rahimi-Esbo, Mazaher, Mohammadyari, Reza, ., Vandana
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Acta scientiarum. Technology (Online)
• Texto Completo: http://www.periodicos.uem.br/ojs/index.php/ActaSciTechnol/article/view/37348
• topic: heat transfer; Nusselt number; friction factor; Reynolds number; laminar flow.

 A comparative investigation of enhanced heat transfer and friction factor by insertion of twisted tapes consisting of alternate axes and regularly spaced tapes in a round tube under wall heat flux condition is presented in this paper. This effort encompassed the flow velocity to be in range of 500 < Re < 1750. All verifications are assumed to be in laminar condition. The two scenarios are verified using numerical procedure, CFD tools, for two types of twisted tapes: short width twisted tape and center cleared twisted tape. The results show that in both types, using alternate axes improved thermal properties. Also the tube friction factor which represents the flow resistance grows with alternate axes twisted tapes. Investigation of regularly spaced twisted tapes also showed that putting the tapes in closer distance can improve flow disturbance. While rotating the middle part helped the flow disturbance, the amount of rotation is also important. Investigation of the free space between twisted tapes compound with the rotation effects showed that the twisted tapes set with smaller space ratios can give better thermal performance.