Lecture ACHEMA CFD

As part of the ACHEMA PRAXISforums, Efraim Riess-Gonzalez will present his lecture on ” The Local Analysis of Velocity Gradients in Stirred Tank Reactors Using Computational Fluid Dynamics Simulations” on Wednesday, 24.8.2022, at 11:10 am, H12.0 – Expert Forum.

The numerical simulation of fluids, better known as CFD (computational fluid dynamics), is nowadays a proven technology that has reached the level of accuracy and robustness that is required in order to be used as a standard tool for the analysis and design of stirred tank reactors, over the last years. Typical unit operation for which CFD can be used are, among many others: homogenization, suspension of solid particles, dispersion of liquid/liquid and liquid/gas systems, heat transfers, etc. On the top of that, the ability to numerically analyze a reactor at each location over the entire fluid volume opens up entire new possibilities.

In chemical or biological stirred tank reactors containing shear-sensitive organism or compounds, the only method regarding the shear-forces to design the mixing equipment was to calculate the averaged velocity gradient (also known as G value [1/s]). This is a global measure for the total dissipated energy into the reactor volume. With the help of CFD simulation shear forces and velocity gradients can be locally quantified and analyzed. The statistical evaluation of volumetric data can help to better understand the reactor behavior in order to optimize processes and also offers a new tool when designing novel mixer geometries that are able to smoothly introduce mechanical energy into the liquid media with lower high peak velocity gradients.

The ACHEMA PRAXISforums are held in the immediate vicinity of the respective exhibition group and focus on industrial applications, new products and services in chemical engineering, biotechnology and the process industry.