30 Jul 2025
What really happens when a reaction unfolds in a real system?
Not just chemistry but fluid flow, heat transfer, and complex geometries all influence the outcome.
Whether it’s a stirred tank, a baking oven, or even a human body, chemical reactions don’t occur in isolation. That’s where Computational Fluid Dynamics (CFD) makes a difference, especially when paired with Reaction Kinetics.
By combining these two, we can simulate not just what reactions happen, but how, where, and under which conditions, in both time and space.
From predicting mixing behaviour and temperature gradients to understanding reaction hotspots and residence times, CFD + Reaction Kinetics creates a powerful modelling framework. This isn’t just theoretical, it’s being used to optimise processes in food science, pharma, chemical engineering, energy, and biosystems.
When reaction occur in real-world systems, whether that is a stirred tank, a baking oven, mixed ingredients in a production line or even inside a human body, those reactions are rarely taking place in isolation. When a reaction takes place, there is more that is going in such as heat, mass transfer and fluid motion, all playing vital roles in how that reaction unfolds and vice-versa. That is where Computational Fluid Dynamics (CFD) comes into play. CFD is a numerical method that simulates how fluids (liquids and gases) move and interact with their environment. And when CFD is combined with reaction kinetics it enables us to model not just where and how fast a reaction occurs, but also how it evolves in space and time as well as under dynamic physical conditions.
CFD and Reaction Kinetics work together to understand various topics. Firstly, with Flow Modelling, CFD solves the Navier-Stokes equations to predict velocity, pressure and turbulence of a fluid in a system, helping define how the reactants are transported or mixed throughout the domain. Through Heat and Mass transfer, CFD tracks temperature distributions (especially important for temperature-sensitive reactions) and how substances diffuse or convert within the fluid. After this you work on the integration of Reaction Kinetics into the CFD model, by embedding rate equations for chemical reactions and these are evaluated at every step and every point in space based on local concentration and temperatures. Once the model is built, you can carry out a coupled simulation. This is because as the system evolves, CFD continuously updates how flow affects reaction rates and vice versa since chemical reactions can release or absorb heat, or alter viscosity and density, feeding into the flow field. The output of this, is a model providing rich spatial and temporal data on concentration or reactants and products, temperature profiles, reaction rates at different locations as well as fluid velocities and mixing behaviour.
CFD coupled with Reaction Kinetics can be applied across many fields such as in Food and Sensory Science, in Pharmaceuticals, in Chemical Engineering, in Combustion and Energy as well as in Environmental and Biological systems. CFD coupled with Reactions Kinetics in essence captures complexity and heterogeneity of real systems making it possible to optimise reactor design and process conditions, improve energy efficiency, avoid unwanted by-products/hotspots, control quality and consistency of outputs as well as reduce experimental costs through simulation. CFD coupled with Reaction Kinetics therefore bridges the gap between theory and practice, giving scientists and engineers a virtual lab to explore, design and improve systems with precision.