Computational fluid dynamics (CFD): a revolutionary tool for the water industry.

To be able to plan and prepare for future problematic events whether it is pandemics, floods or infrastructure disruptions, is essential for the water sector to maintain service.

Looking at  the Caribbean and the US Eastern Seaboard, the hurricane season runs from June to November in this region with recordings of heaviest extreme weather events in recent weeks. These storms can overwhelm the water treatment and supply system. Digital twins can help here to prepare for such a scenario through a computer model that virtually reflects and simulates a system.

The use of Computational Fluid Dynamics (CFD) provides a better understanding of the behaviour of the system for improved design and operation.

 

What are Computational Fluid Dynamics?

Increasing computational power has been rapidly evolving Computational Fluid Dynamics (CFD). Water and wastewater treatment process design and the scale-up of novel technologies have always relied heavily on trial-and-error based physical testing and experimenting.

With the CFD a powerful computer simulation tool steps in. It provides a revolutionary alternative as it allows high resolution calculation and visualisation of mixing and reactions inside water and wastewater treatment systems, in 3D and at real scale. While the core of CFD relies on fluid physics equations, multiphase simulations (i.e. gases and solids in liquids) and direct integration of (bio)chemical conversions have become mature engineering frameworks.

CFD as a digital engineering tool has four major benefits for utilities, technology manufacturers and engineering firms:

1. Cost saving: significant capital expenditure (CapEx) and operational costs (OpEx) savings by proactive avoidance of operational issues, optimal energy usage, smart chemical dosing and efficient and less conservative design;
2. Time saving: months to years of trailing and piloting can be bypassed. Furthermore, technology developers have the additional benefit of significantly shortening their time to market. The latter is more relevant than ever!
3. Optimal performance: systems are designed and operated optimally in view of envisioned quality requirements. Both performance and reliability can be increased dramatically, with less input, footprint, etc.;
4. Enhanced confidence and learning: the in-depth information provided by CFD offers unprecedented learning, impacting future decisions and confidence in the process.

The real power of CFD lies in ‘what-if’ testing, meaning that ample operational and/or design modifications can be tested without the need of any onsite testing. The recent developments of CFD models and computational power have opened the door for virtual prototyping (e.g. inventing new equipment prior to really building it) and virtual piloting (e.g. scaling up a system with several orders of magnitude without intermediate real-life piloting).

Furthermore, CFD allows for a ‘quality by design’ approach: design the processes with envisioned specs in mind, instead of trying to compensate for suboptimal design with expensive operational measures at a later stage. The contribution to digitalisation is a revolutionary way of process design and operation based on today’s computational power.

With the dramatic increase in computational power, the last barrier standing in the way of large-scale global deployment as a standard engineering tool has been removed. The water industry is embracing CFD at a rapid pace.

In the future, every major engineering and design project will heavily rely on CFD, very similar to what is now happening in the car and aerospace industry where every device goes through a computer-based design stage. CFD will create important innovation opportunities, i.e. the virtual prototyping and development of novel, disruptive technologies prior to any physical testing. Additionally, computational power is expected to increase, providing opportunities for real-time adoption and the creation of extremely realistic digital twins.

 

Additional information

To learn more about the use of modelling in the water rector, read here: https://www.iwapublishing.com/books/bookarticle-author-editors/ingmar-nopens.

Additional blog of the use of CFD for sustainable water treatment can be found here: https://iwa-network.org/computational-fluid-dynamics-a-key-tool-in-moving-towards-sustainable-water-treatment/.

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