Redução de arraste e degradação de polímeros flexíveis em escoamentos turbulentos em dutos

• Autor(a) principal: Silva, Lucas Antônio Silveira
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/9773
• topic: Polymers; Turbulent flow; Drag reduction; Polymer degradation; Engenharia Mecânica; Escoamento; Polímeros; Redução de arraste; Degradação polimérica; 621

The reduction of friction factor in turbulent flows, by additives injection, has been studied since the middle of the last century and has received wide scientific and industrial attention until now. Among the additives most used, polymers (Polyacrylamide, polyisobutylene, Xanthan Gum), surfactant additives, fiber (nylon, cotton and asbestos), besides of paper pulp and gas bubbles calls for attention. The drag reduction using polymeric additives is a phenomenon that was reported for first time by Toms (1948). The author showed that the addition of little quantities of high molar weight polymers in a turbulent flow, reduces the friction factor significantly. Since then the phenomenon has been widely studied, due to the big benefits achieved in practical applications in several engineering areas. The example most famous up to now is the transport of crude oil in the ”Trans-Alasca Pipe Line” with 1300 kilometers of length where adding polymeric additives in the range of ppm lead to approximately 30% of drag reduction. The present work has the objective of assessing the phenomenon of friction factor reduction in turbulent pipe flows with addition of flexible polymers. For this project, it used an experimental turbulent pipe flow apparatus with control of flow rate, pressure and temperature. The results are focused in analyze of mechanical degradation of the polymers and its relation with the concentration, molecular weight and Reynolds number. The results are shown in terms of the drag reduction parameter in function of the number of passes, in which the equivalent length due all passes made in the experimental plant is about 400 meters.