Obtaining fow curve for viscoplastic fuids through inclined open‑channel apparatus

• Autor(a) principal: Sáo, Yuri Taglier
• Data de Publicação: 2021
• Outros Autores: Pereira, João Batista, Fiorot, Guilherme Henrique, Maciel, Geraldo de Freitas
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/222238
• topic: Escoamento de fluidos; Reometria; Fluidos não newtonianos; Canais abertos; Flow curve determination; Rheometry; Non-newtonian fuids; Inclined open-channel; Experimental method

Non-Newtonian fuids are commonly seen in industrial processes, such as those of the oil and mining industry, and in natural fows, like dam ruptures, landslides or mud fows. The hydrodynamic modeling of such processes/phenomena is directly linked to the rheological properties of the fowing fuid, usually characterized through rheometers. The high cost of rheometers and possible inaccessibility for certain applications demand for research of alternative rheometric methods. In order to assess the problem, the present work discusses a detailed experimental methodology to evaluate if the steady and uniform fow in an inclined channel is able to produce the fow curve for the test fuid carbopol 996 gel and work as an alternative rheometer. In order to estimate the shear rates and shear stresses, we measured the normal depth (ultrasonic technique), specifc discharge (manual gravimetric method) and free surface velocity (manually and with laser barrier sensors). Based on the theoretical solutions, a simplifed ftting procedure was adopted to make possible the assessment of shear rate and shear stress through the experimental data. The obtained fow curves were then compared with the reference fow curve, determined by a commercial R/S rheometer. Results showed that the experimental methods were able to provide the fow curves within acceptable uncertainty and the defned methodology detailed in the work can estimate satisfactorily the fow curve of non-Newtonian fuids. Finally, we highlighted that the wide channel hypothesis is the strongest condition to be guaranteed in order to obtain precise fow curves through the methodology present in this work.