This paper explores the effect of impeller design on the chaotic mixing in a helical ribbon mixer. Numerical simulations using the Smoothed Particle Hydrodynamics (SPH) method are used to solve for the fluid flow around the moving impellor. The mixing flow is visualised by extracting the hyperbolic Lagrangian Coherent Structures (LCS) of the flow from the Finite-Time Lyapunov Exponent (FTLE) fi...

Air sparging (AS) is a commonly applied method for treating groundwater contaminated with volatile organic compounds (VOCs). When using a constant injection of air (continuous mode), a decline in remediation efficiency is often observed, resulting from insufficient mixing of contaminants at the pore scale. It is well known that turning the injection on and off (pulsed mode) may lead to a better...

The turbulent flow field generated in a baffled stirred tank was computed by large eddy simulation (LED) and the flow field was developed using the Sliding Mesh (SM) approach. In this CFD study, mixing times and power number have been determined for a vessel agitated by a 6-blade Rushton turbine. The predicted results were compared with the published experimental data. The satisfactory results ...

Knowledge and control of mixing in batch processes can prevent yield losses during scale-up. Therefore, this study, a new heat-mixing model based ono the measurement heat distribution after an applied pulse, is proposed. The was developed to predict mesomixing support scale-up, scale-down, design optimisation reactors. proposed considers influences rotational speed, stirrer type, solvent, stirr...

A CFD (Computational Fluid Dynamics) benchmark calculation for a steam blowdown test was performed for 30 seconds to develop the methodology for a numerical analysis of the thermal mixing between steam and subcooled water and to apply it to APR1400 (Advanced Power Reactor 1400MWe). In the CFD analysis, the steam condensation phenomenon by a direct contact was simulated by the so-called condensa...

This paper presents experimental studies on thermal stratification in chilled-water storage systems. A fibreglass storage tank in static and dynamic modes of operation is used. The parameters varied are aspect ratio, flow rates, initial temperature difference and thickness of insulation. Emphasis is given to the effects of mixing at the inlet, leading to the definition of the mixing coefficient...

Impeller stirred tanks (STR) are commonly used in the chemical processing industries (CPI) for a variety of mixing and blending technologies. In the present research, a numerical study of flow and mixing inside turbulently agitated tanks were carried out. An efficient solution algorithm was developed to solve turbulent flow inside stirred tanks where the boundary conditions for moving impeller ...

Computational Fluid Dynamics (CFD) was used to simulate the mixing characteristics of four different circular anaerobic digester tanks (diameters of 13.7, 21.3, 30.5, and 33.5m) equipped with single and multiple draft impeller tube mixers. Rates of mixing of step and slug injection of tracers were calculated from which digester volume turnover time (DVTT), mixture diffusion time (MDT), and hydr...