"People often think fan development starts with a new blade or fan housing design, in reality, it starts with understanding how air behaves."
Bram - Aerodynamic Engineer at Vostermans Ventilation
Unlike the blades or the motor, airflow cannot be seen. Yet it determines almost every aspect of a fan's performance. Efficiency, airflow, pressure development, throw distance and even sound all depend on how air moves through and around the fan. Understanding airflow is therefore key to developing better-performing fans at Vostermans Ventilation.
Developing a new fan is rarely about finding a single breakthrough. More often, it is about asking lots of small questions.
How does a different blade profile influence efficiency?
Can the airflow be guided more smoothly through the fan?
What happens when the geometry of the fan housing is modified?
How much energy is lost due to turbulence?
How can aerodynamic noise be reduced without compromising airflow?
"Every design choice influences the airflow," Bram explains. "Our challenge is understanding exactly how those choices affect the final performance of the fan."
Finding those answers using physical prototypes alone would take an enormous amount of time. This is where Computational Fluid Dynamics (CFD) has transformed the engineering process.
CFD allows engineers to simulate airflow before the first prototype is manufactured. Instead of building multiple physical designs, engineers first evaluate ideas in a virtual environment. Airflow velocity, pressure distribution and turbulent flow structures become visible, providing valuable insight into how a fan behaves long before laboratory testing begins.
"The simulation itself isn't the goal," Bram says. "The goal is understanding the physics behind what we see." By visualizing airflow, engineers can identify aerodynamic losses, compare alternative designs and better understand why one concept performs differently from another.
*Airflow visualized using CFD
One of the most interesting aspects of aerodynamics is that seemingly minor details can have a measurable impact on performance. Take the clearance between the blade tip and the fan housing. Although only a few millimeters wide, this gap allows air to flow around the blade tip instead of through the fan. The resulting tip vortex represents an aerodynamic loss that engineers aim to minimize. CFD makes these flow phenomena visible and helps engineers understand how blade geometry, tip clearance and housing design influence overall performance.
The value of CFD becomes most apparent when it contributes to products that perform exceptionally well in practice. During the development of the Multifan AirBreeze, CFD played an important role in evaluating numerous aerodynamic concepts before prototypes entered laboratory testing. By combining aerodynamic expertise, CFD simulations and extensive laboratory validation, engineers optimized the fan for airflow, energy efficiency and acoustic performance.
The same engineering philosophy was applied during the development of the Multifan Venturon. Different fan housing designs, blade geometries and airflow characteristics were analyzed, allowing engineers to make informed design decisions throughout the development process.
Today, both product families are recognized as belonging to the top of the market in terms of performance, energy efficiency and sound levels. While every successful product is the result of many engineering disciplines working together, CFD has become an indispensable tool for understanding and optimizing aerodynamic performance.
Although CFD has become an indispensable engineering tool, simulation is never the final answer. Every numerical model is validated using laboratory measurements to ensure that the virtual predictions accurately represent reality. "A simulation without validation is just a visualization," Bram says. By continuously comparing simulations with measured performance, engineers improve both their numerical models and their understanding of airflow.
For Bram, every project starts with curiosity. No two fan designs behave exactly the same, and every new development reveals something new about airflow. "The more we understand the physics, the better our engineering decisions become. That continuous pursuit of knowledge is what drives our innovation at Vostermans Ventilation. Because designing better fans doesn't start with motors and impellers. It starts with understanding the invisible.”