Study of Hydrodynamics and Upscaling of Immiscible Fluid Stirred Tank using Computational Fluid Dynamics Simulation

Abstract

Stirred tanks are prevalent in various industries, including chemical, biochemical, and pharmaceutical industries. These reactors are suitable for ensuring efficient mass and heat transfer because adequate mixing can be achieved. Numerous studies have been conducted on small-scale stirred-tank reactors. However, upscaling such reactors is challenging because of the complex flow behavior inside the system, especially for the mixing of immiscible liquid–liquid systems. Thus, the objectives of this study were to examine the flow behavior and upscale an immiscible liquid–liquid stirred tank using CFD simulation by investigating a flat-bottomed stirred tank reactor, equipped with a six-blade Rushton turbine. The simulated results were in good agreement with those obtained experimentally. The scale of the reactor significantly affects the hydrodynamic behavior, and the uniformity of the radial distribution of the velocity decreases with increasing Reynolds number. Furthermore, the upscaling criteria were evaluated for geometric similarity and equal mixing times. The proposed scaling law reliably scaled up the immiscible liquid–liquid mixing in a stirred tank with a difference in the range of ±10%.

CFD simulation of silica dispersion/natural rubber latex mixing for high silica content rubber composite production

“…The velocity of agitation exhibited variability in both the impeller and rotor regions. Based on the grid sensitivity study conducted in our previous work, 29 an optimum grid of 94 961 grids was utilized in this study. The numerical method and model parameters employed in this study were consistent with those established in our previous work.…”

“…The numerical method and model parameters employed in this study were consistent with those established in our previous work. 29 Simulation results based on those parameters were successfully validated against experimental data. Further validation of these parameters was conducted by comparing the tip velocity as shown in Fig.…”

“…The details of the mathematical model can be found in our previous work. 29 Fig. 4 The velocity vector plot of a dispersed phase in small (a-d) and large (e-h) stirred tanks equipped with a Ruston turbine with 90°6 blades, 45°6 blades, 90°4 blades and 45°4 blades.…”

“…[53][54][55] Various approaches and relationships for determining mixing time have been presented in the literature. 56 Some researchers, 29,57 have employed Computational Fluid Dynamics (CFD) simulations to calculate mixing time in stirred tanks. In this work, mixing time calculation based on Phumnok's proposed was utilized, and detailed information can be found in the ref.…”

“…26,27 In such systems, the viscosity disparity between the continuous and dispersed phases signicantly impacts the mixing process. CFD serves as a powerful tool for analyzing ow behavior, 28,29 understanding complex interactions between phases, 30,31 and optimizing mixing performance. [32][33][34] Engineers can optimize impeller geometry, rotational speed, and baffling arrangements based on CFD results to achieve improved mixing performance.…”