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Hydrocylones offer a process intensified environment for rapid, high-throughput and relatively sharp particle classification or phase separation. One of the main performance limitations of hydrocyclone is bypassing of fines to the underflow. To address this limitation, a novel design modification of fitting thin concentric rings to the cylindro-conical section has been proposed. The Computational Fluid Dynamics (CFD) modeling based methodology has been adopted to validate the hypothesis. Predictions using Realizable k-e, Reynolds Stress Model (RSM), and Large Eddy Simulation Wall Adopting Local Eddy viscosity (LES-WALE) turbulence models has revealed that LES-WALE matched better with the experimental observations. The experimental data included overall performance parameters and detailed observations of axial and tangential velocity profiles across the hydrocyclone. The validated CFD model and the methodology was then used to predict the behavior of the proposed designs. They established that the modifications held promise in reducing the bypass with additional benefits of sharper separation curve and finer D50.

Mixing is an important unit operation in the process industry. Ensuring homogeneity of slurry or emulsion is critical for subsequent processing or to improve the efficacy of reactions, and heat/mass transfer. Mixing in stirred tanks is typically improved through baffles. While baffles are good at breaking vortices, they contribute to energy dissipation. Most of the previous research focused on improving impeller designs, its position and operation. Limited investigations exist that probe the design improvements of baffles. In this work, through an extensive computational fluid dynamics study involving multi-phase flow simulations using volume of fluid (VOF) approach and Lagrangian particle tracking, we have designed an effective mixing system with optimum baffling. The newly designed baffle, called interface baffle, is placed at the interface between air and liquid to break the vortex and redirect the flow to the center. The predicted mixing behavior is experimentally validated in a pilot scale tank of 100 liter capacity. Particle size distribution measurements of samples from the top and the bottom of the tank were used to establish the effectiveness of mixing. Experiments were conducted under three different tank conditions, namely, without baffles, traditionally baffled, and interface baffled. Interface baffled system provided much better mixing characteristics.