Analysis of Performance in Homogenous Mixing Systems Using Ansys

Abstract

Objective: This study aims to understand the mixing phenomenon and the mass transfer occurring simultaneously by simulating the system using Ansys Fluent. Methods: Taking liquid-liquid mixing into account, a simple agitated mixing system can be compared to a CSTR, utilizing the impeller to provide forced convection mixing conditions. The same forced convection can be achieved using high flow rates in smooth vessels instead of mechanical impellers to produce the convection current. The systems are then stimulated using Ansys Fluent software to calculate the mass transfer coefficient and several dimensionless numbers, such as the Reynolds number, Sherwood number, and Schmidt number, in order to understand the underlying mechanism of mass transfer in mixing systems. Results: It has been observed that a 90° pitch impeller tends to have a higher NP value as compared to a 45° pitch impeller. Overall performance can be compared by the time taken to achieve homogeneity at the same angular rotational speed of 100 rpm. Thus, in terms of performance, it can be concluded that 45° pitch is (inclined) > 90° pitch is (in-centre) > 45° pitch (in-centre) is > 90° pitch (inclined). Conclusion: The simulation model used in this study is useful for a combination of CFD model predictions using the sliding mesh approach and the VOF model. It can be applied to study the effect of different designs on the flow pattern and mixing time for a set of axial flow impellers.