NUMERICAL SIMULATION SHEAR-THICKENING FLUID THROUGH A SMALL-SCALED HEAT EXCHANGER

Abstract

This paper aims to predict the behavior of a complex fluid though a small-sized thermal exchanger. The fluid used is of shear-thickening type of power-law index (n = 1.4) and Prandtl number (Pr = 50). The Ostwald model was utilized to define the dynamic viscosity. The exchanger consists of three rectangular cross-section tubes placed inside a thermally insulated chamber. The enclosure contains two ports for the entry and exit of the complex fluid. The complex fluid enters the chamber from the first port at a constant speed and at a low temperature, and then it passes around the hot tubes to be cooled. The rheological behavior of a fluid is defined by Ostwald equation, while the intensity of thermal buoyancy was modeled by Boussinesq approximation. The results showed that the increase of the velocity of the flow at the entrance increases the instability of the flow. Increasing the intensity of thermal buoyancy reduces the cooling process of the hot upper body.