Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
Numerical analysis of the rheological properties effects over the re-start flow
Submission Author:
Daniel Dall Onder dos Santos , MG , Brazil
Co-Authors:
Luiz Paulo Borges Miranda, Daniel Dall Onder dos Santos
Presenter: Luiz Paulo Borges Miranda
doi://10.26678/ABCM.ENCIT2022.CIT22-0426
Abstract
The re-start problem is a relevant issue in several applications, especially when non-Newtonian behaviors are considered. For example: during the oil transport, if the system shuts down and the fluid temperature falls below a certain point, the oil can present a rheological behavior that can completely block the pipeline. If at a Newtonian isothermal internal flow the Reynolds number is the main dimensionless quantity necessary to define the flow, when a non-Newtonian behavior is considered, at least one more dimensionless quantity is needed to describe the flow. Therefore, the present paper search to discuss the effects of some dimensionless quantities related to these non-Newtonian behaviors over a transient flow inside a planar channel. These dimensionless quantities describe the rheological behavior of the fluid, considering, for example, the local shear rate. The flow was solved using the open-source CFD software OpenFOAM, adopting the isothermal and Poiseuille flow conditions, where a pressure gradient is imposed over a static flow. The present results show how these dimensionless quantities affect the time to reach the developed flow condition. Increasing the flow behavior index decreases the time to reach the developed flow condition while increasing the plastic number increases this time. These dimensionless quantities change the viscous forces profile, and therefore also change the acceleration of the flow.
Keywords
OpenFOAM, Thixotropy, Flow Re-start, plastic number
