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Key research themes
1. How does stirrer design and operation affect mixing efficiency and fluid dynamics in various applications?
This research area investigates the influence of stirrer geometry, orientation, operational parameters (e.g., speed, frequency), and vessel design (e.g., baffles) on mixing performance, fluid flow patterns, turbulence, and mass transfer efficiency. Understanding these factors is critical for optimizing industrial and laboratory mixing processes in metallurgy, chemical processing, food production, and biochemical applications.
Key finding: Experimental results show that baffle geometry significantly affects fluid flow patterns and power requirements in stirred vessels, with longer baffles increasing power number and creating more effective mixing. Various... Read more
Key finding: The study identified that horizontal orientation of stirred mills, exemplified by IsaMill, offers more efficient scale-up and produces finer particles with narrower size distributions compared to vertical mills like HIGMill.... Read more
Key finding: Using PDE-constrained gradient-based optimization, the study determined that irregular stirrer cross-sectional shapes and unsteady velocity protocols substantially enhance mixing quality. Start-stop vortex shedding induced by... Read more
Key finding: Physical and multiphase modeling showed that slag thickness directly controls turbulence near the metal-slag interface during argon-stirred ladle operations. Thin slag layers reduce mixing time and limit slag entrainment,... Read more
Key finding: Experiments revealed that increasing viscosity raises power consumption but adversely affects oxygen mass transfer rates in unbaffled stirred tanks. Mass transfer increases with stirrer speed up to a critical vortex formation... Read more
2. What are the material flow patterns and microstructural effects during friction stir processing (FSP) with various stirrer and tool designs?
This theme covers the investigation of material flow, temperature fields, and microstructural evolution induced by friction stir processing using different tool configurations (e.g., bobbin tools, pin-less tools, cooling variations). These studies are vital for optimizing FSP to achieve desired microstructural refinements and mechanical properties in metals, especially aluminum alloys.
Key finding: Numerical modeling revealed that in friction stir surfacing without a pin, material is transported from the tool shoulder's leading edge toward the retreating side, forming a vortex flow zone. Temperature distributions are... Read more
Key finding: The study applied Response Surface Methodology to optimize bobbin tool FSP parameters, showing that rotational speed and travel speed significantly affect processing temperature, microstructure, and mechanical properties. The... Read more
Key finding: Experimental investigations demonstrated that cooling methods during FSP, such as angled cooled air jets, enhance grain refinement and improve material hardness and wear resistance. The study of different pin geometries in... Read more
3. How can modeling and measurement techniques optimize mixing times and rheological behavior in stirred systems for viscous and particulate materials?
This research area focuses on developing quantitative models and experimental methods to predict and optimize mixing time, rheological properties, and particle distribution in stirred vessels. It includes studies on viscous liquids, granular solids, and multiphase flows, aiming to improve scale-up and control of industrial mixing processes in chemical, pharmaceutical, and materials engineering.
Key finding: The authors developed quadratic and power law regression models relating mixing time to tracer volume, liquid viscosity, and impeller speed. Results showed mixing time saturation beyond a critical Reynolds number and slope... Read more
Key finding: Using GPU-accelerated Discrete Element Method (DEM) simulations calibrated with experiments, the study showed that increasing impeller rotational speed enhances mixing of non-spherical (cubical and cylindrical) particles in a... Read more
Key finding: Investigations showed that static mixers without moving parts can achieve homogenous mixing of free-flowing particulate solids by repeated splitting and reuniting flows. Mixing quality depends strongly on element number,... Read more
Key finding: The development of a novel mechanical stirring system allowed controlled semisolid processing and rheometric measurements on A380 aluminum alloy. The system optimized viscosity as a key parameter for microstructure, showing... Read more