Effect of shear-thinning behavior on fluid temperature distribution mixed by single rotor

Abstract

The mixing process is used not only to homogenize the materials, but also to bring out better functionality by mixing different materials. In the mixing process, temperature control during mixing is important to prevent thermal deterioration of the material and control chemical reactions. In this study, a 3D model was used to numerically simulate the flow field around a single rotating rotor in a partially filled chamber to investigate the thermal flow characteristics of a highly viscous fluid. The liquids examined contained glycerin, a Newtonian fluid, and carboxymethyl cellulose (CMC) aqueous solution, a non-Newtonian fluid. A three-wing rotor was chosen as the mixing rotor and the shear heating of viscous fluid was modeled by heating the tip of the rotor wing with a heater. Obtained simulation results of the temperature distribution around the rotor was agreed well with the independently performed experimental results. Evaluation of thermal flow properties was performed using history particles. Also, in order to analyze the temperature field, the flow rate through the rotor tip was used to classify the effect on the flow field. As a result, it was found that there was a correlation between the shear-thinning property and the temperature non-uniformity, and the flow rate ratio between the passing flow rate and the circulating flow rate due to the shear-thinning property of the fluid affected the thermal diffusion of the high temperature part.

Keywords

• mixer
• stirrer
• shear-thinning viscosity
• non-newtonian
• thermal history
• flow analysis