Solving Mixing and Simulation Challenges in Process Development: A Chat with John Thomas of M-Star Simulations

9/13   in the series Industry Interviews

The Process Development Symposium (PDS) will take place virtually from June 1-3. The meeting provides attendees with an opportunity to exchange wisdom, knowledge, and personal experience in process development in areas like designing robust, flexible, and sustainable processes. I had a chance to interview talk with John Thomas, an application engineer at M-Star CFD, as well as some of the companies that have used M-Star’s technology to solve challenges they face in mixing and simulation.

Register for the meeting here to listen to M-Star’s full presentation and network with professionals working in the field. M-Star’s talk will take place on Wednesday, June 3rd, from 10:50-11:05 EDT.

What are the key challenges you focus on solving in process development?

Companies face many mixing and simulation challenges ranging from multiphase gas/liquid bioreactors to chemically reactive systems with time-dependent rheology. These are difficult to solve because of long simulation setup times and large computational requirements. We aim to accurately simulate real-world systems to help engineering professionals and advanced researchers. I’ve asked two of our partners, AstraZeneca and Philadelphia Mixing Solutions, to share their challenges that we have worked together to solve.


We used M-Star CFD’s software to simulate the dynamic time evolution process of the UF/DF protein concentration step. Concurrent volume reduction, protein concentration and viscosity increase were simulated with retentate tank outlet and return flow with permeate draw off over a > 6 fold volume reduction step. Real-time video rendering of the entire concentration step provides insight into the fluid dynamics such as shear at the air/liquid interface, mixing time, and tendency to short circuit the retentate return line to the tank outlet.

The M-Star CFD simulation rendering allows engineers and scientists to see via video and graphics quantitative time-evolving estimates of shear forces at the air/liquid interface, effect of volume/viscosity on mix times, and visual representation of flow patterns in the vessel during concentrations. This fluid dynamic insight can be used to optimize operating conditions in the UF/DF step to minimize protein damage and improve homogeneity in the process.

Philadelphia Mixing Solutions

In addition to designing new, purpose-built agitators we support clients in retrofitting or adapting existing assets to support process changes and new products. These situations often have many viable approaches. M-Star helps us address multiple options more quickly and completely than we otherwise could. On the front end, model import doesn’t require simplification, and “meshing,” is eliminated from our workflow, thanks to the solution method used by M-Star; little time is lost when updating geometry allowing iteration.

When running a simulation, the GPU based solver delivers a fully transient representation of a system more quickly than a typical RANS solver will provide time-averaged output. Transient data is available as it’s produced, which allows us to use preliminary output to inform iterative design refinements more quickly. On the back end, macro- and meso-scale turbulence and flow drive the criteria (blend time, residence time distributions, etc.) we use to characterize mixing processes and those phenomena are more directly represented by M-Star’s solution method than through others.

Making fewer assumptions improves confidence in the output we review. The time savings and improved confidence offered by the software allows us to more thoroughly investigate potential improvements in open-ended situations, empowering our customers to choose the ideal solution for their process.

Can you tell us more about how M-Star is able develop these solutions for its partners?

M-Star CFD is software that simulates real-world systems with unprecedented accuracy. The high-fidelity results are driven by Large Eddy Simulation and advanced lattice-Boltzmann algorithms than run entirely on GPUs. As a fully time-resolved approach, it is easy to include multi-fluid, multi-phase, and multi-physics effects into any model. Simulations are a snap to set up, run, and post-processes on Windows workstations or HPC. The workflow is stream-lined and tolerant of imperfect CAD files. Moreover, processes simulation setup and execution times are measured in minutes and hours, rather than days and weeks that are typical of legacy CFD.

Join us at the Virtual Process Development Symposium on Wednesday, June 3rd, from 10:50-11:05 EDT to learn more!

John Thomas

John Thomas is an application engineer at M-Star CFD. Prior to joining M-Star CFD, he was a research scientist at Johns Hopkins.

Disclosure: This post is sponsored by M-Star and reflects their views, opinions, and insights.