Simulação numérica de escoamentos viscoplásticos com transferência de calor através do software OpenFOAM

Abstract

The main objective of this work is to develop, validate and apply an OpenFOAMr routine able to solve non-Newtonian fluid flows, adopting the generalized Newtonian model. Others software with the same characteristics are often not accessible to the majority of the scientific community, either because they are restricted to certain types of flows or because of the cost of their license. Thus, this work seeks to develop an inexpensive and versatile tool to study of this class of flows. In order to achieve this goal, the development of the code is presented and discussed, especially due to the important numerical obstacle imposed by some non-Newtonian behaviors, such as viscoplastic behavior, for example. Then, the routines were validated, comparing the results obtained in simulations of natural convection flows inside a square enclosure with the results found in the literature. The results obtained with the proposed routine presented a high correlation with the results of the literature, and thus the proposed routines were used to solve viscoplastic fluid flows inside a planar channel with an expansion followed by an abrupt contraction. The dimensionless groups that define this flow are the Reynolds number, the Pradtl number, the jump number, the plastic number, the behavior index and the viscosity plateau for high shear rates. Among these, the influence of the Reynolds number, of the plastic number, and of the behavior index were analyzed. The results were obtained in terms of the mean Nusselt number, the head loss and the displacement efficiency.