High performance in terms of thermal mixing of non-Newtonian fluids using open chaotic flow: numerical investigations

Abstract

In the present work, the thermal mixing between two pseudo plastic fluids within different geometries (C-shaped and straight ducts) is studied numerically as a function of the generalized Reynolds number ranged from 50 to 200 in addition to the power law index values ranging from 0.5 to 1. The C-shaped geometry generates a chaotic flow, whereas the flow in the straight channel is regular and laminar. Numerical computations were conducted in the current study in order to achieve the mentioned target, using a CFD code. Dynamic and thermal validation of the used model configuration is realized and compared with previous works in literature. For all simulations, the inlet section of each channel is divided into two parts, horizontally and vertically. In which, for one part the fluid is injected at 330 K and in the other part the fluid is released at 300 K. Evaluation of the mixing quality is examined by computing the mixing degree Dm, and the probability density function PDF. The two criteria confirmed that the chaotic geometry gives good performances in terms of temperature homogenization compared to that obtained in the straight channel. Moreover, the mixing time does not exceed one second using the chaotic geometry, while in the straight geometry is in the order of some minutes.