Experimental investigation of the fluid flow in a complex force field with induction heating – FLOWHEAT

• Applicants: Dr. Kaspars Dadzis; Dr. Olf Pätzold
• Subject Area: Fluid Mechanics ; Chemical and Thermal Process Engineering
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 584692867

The project aims at gaining detailed knowledge about flow phenomena in inductively heated melts as the key for a fundamental understanding of the heat and mass transport in a broad range of metallurgical and crystal growth processes. The melt flow in these systems is driven by a complex field of volume and contact forces. They are related to local heat input and Lorentz force at the melt boundaries resulting from high-frequency (HF) induction as well as to melt free surfaces in contact with a gas phase and melt surfaces in contact with temperature-controlled and/or rotating solid walls including solid-liquid phase boundaries. The combination of these phenomena defines a new class of fluid dynamic problems. In this project, we address fluid flows driven by a complex force field including HF induction on the basis of the concept of experimental flow modelling at low temperatures <100°C. This approach involves the development of new model setups for the experimental investigation of melt and gas flows. The Silicon Granulate Crucible Technique (Si-GC), which has been developed at the IKZ, will be taken as reference setup, because this technique combines many project-relevant flow scenarios. Low-melting gallium compounds will be applied as model materials for the melt. The influence of the high-frequency induction will be scaled to lower frequencies preserving the typical Lorentz force distribution at reduced heat induction. The resulting flow structures will be investigated and visualized using ultrasonic methods including 2D flow mapping and advanced methods of signal processing. The phenomena in gas flows will be investigated by means of a transparent fluid and a refractive-index-matched model setup. The Particle Image Velocimetry (PIV) as a standard full-field optical measurement technique will be applied to investigate the global flow structure. As a result of the model experiments, reference and benchmark cases will be defined to describe and categorize the observed flow phenomena into force balances and stability diagrams. It is also planned to perform numerical simulations of melt and gas flows using the finite volume software OpenFOAM. Such simulations can significantly improve the understanding of the observed flow patterns in 3D, if a sufficient match with the measurements is achieved. The definition of reference cases aims at the missing link between experimental and numerical modelling and will be an important step toward the development of validated numerical models for flow simulation. This approach will contribute to a better understanding of fundamental flow phenomena in the addressed branch of fluid dynamics, such as the structure, stability and threshold behavior, and the related convective heat and mass transport in melt and gas flows.

• DFG Programme: Research Grants
• Co-Investigators: Dr.-Ing. Sven Eckart; Professor Dr.-Ing. Christian Kupsch