Mixing of Complex Fluids with Confined Impinging Jets

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Confined Impinging Jets (CIJs) have been shown to be highly efficient continuous mixers, offering a strong alternative to more traditional and less efficient industrial mixing technologies such as mechanically stirred vessels. In these devices, two or more liquid streams are injected into a confined space by opposed jets. Under appropriate conditions, a hydrodynamic instability promoted by the rapid deceleration of the impinging streams allows for mixing to be achieved rapidly and without moving mechanical parts. When compared to stirred vessels, CIJs can offer a more efficient utilisation of energy for mixing by providing higher and more uniformly distributed energy dissipation rates in the flow. CIJs mixers can prove to be a suitable solution to intensify continuous processes that require a rapid homogenization of streams. Nonetheless, the impact that the complex rheological properties of non-Newtonian fluids can have on the mixing performance is not yet fully understood. Additional studies to offer a more robust and intensified operation of CIJs mixers for processing complex fluids are, thus, still crucial. This project will focus on the computational and experimental study of the flow dynamics and mixing performance of shear-thinning and viscoelastic fluids in CIJs. Numerical simulations of the flow will be obtained with Computational Fluids Dynamics (CFD). Advanced experimental techniques, such as Planar Laser Induced Fluorescence (PLIF) and Particle Image Velocimetry (PIV), will be also used for the characterization of the flow and mixing.