Free Online VKI Seminar - Feedback Control of Liquid Metal Coating

We are happy to invite you to the online seminar on “Feedback Control of Liquid Metal Coating” that will be delivered by Dr. Fabio Pino, Université Libre de Bruxelles / von Karman Institute for Fluid Dynamics on 9 September from 2:00 PM to 3:00 PM.

Abstract: 

Hot-dip galvanizing is an industrial process that protects steel products from corrosion. Ensuring a uniform coating remains challenging due to a fluid instability known as undulation. This work presented solutions to this issue, significantly advancing the field of liquid metal coating.

By immersing and then withdrawing a metal sheet from a bath of molten zinc, a liquid film forms on the sheet’s surface, which then solidifies into a protective layer. Controlling the final coating's thickness involves using gas jets to remove excess zinc from the bath. At withdrawal speeds above 2 m/s, the jets oscillate, triggering the undulation instability, which leads to uneven coatings and increased environmental impact due to additional surface treatments.

This research project developed a feedback control strategy to mitigate the undulation using gas jets and magnetic actuators with limited liquid film observations. The project followed a multidisciplinary approach, integrating reduced order modelling, numerical methods, linear stability analysis, model predictive control, and machine learning control. An analytical reduced-order model of the three-dimensional (3D) liquid film was developed, with the observation point location based on linear stability findings. Control methods based on linear stability analysis were tested on two-dimensional (2D) unstable waves, demonstrating strong performance and revealing intricate physical control mechanisms. Expertise was developed in machine learning control by comparing various methods on flow control test cases. Based on this knowledge, reinforcement learning algorithms were applied to the undulating problem, reducing the wave amplitude by 10% with jets pushing the crests and magnets rising the troughs.

These findings pave the way for industrial applications of the feedback regulator to reduce undulation instability and deepen the understanding of the liquid film dynamics. Integrating machine learning control methods into a novel workflow alongside analytical approaches and simulations, this research offered significant advancements in industrial coating processes. Owing to its versatility, this new methodology holds promise for applications in other engineering domains, such as combustion flows or turbulence control.

Biography:

Fabio holds a Master’s Degree in Aerospace Engineering from Politecnico di Torino and Politecnico di Milano, as well as a Diplôme d’Ingénieur from École Centrale de Lyon. He continued his education with a 2nd level Master in Space Exploration and the VKI Research Master in Fluid Dynamics. Recently, he earned his Ph.D. from Université Libre de Bruxelles (ULB) in partnership with VKI, with a thesis titled "Feedback Control of Liquid Metal Coating."

Please check our eligibility criteria before registering.