Effect of baffles on fluid flow field in stirred tank with floating particles by using PIV

Past and current components-based detailing of particle image velocimetry: A comprehensive review

Particle image velocimetry has been widely used in various sectors from the automotive to aviation, research, and development, energy, medical, turbines, reactors, electronics, education, refrigeration for flow characterization and investigation. In this study, articles examined in open literature containing the particle image velocimetry techniques are reviewed in terms of components, lasers, cameras, lenses, tracers, computers, synchronizers, and seeders. The results of the evaluation are categorized and explained within the tables and figures. It is anticipated that this paper will be a starting point for researchers willing to study in this area and industrial companies willing to include PIV experimenting in their portfolios. In addition, the study shows in detail the advantages and disadvantages of past and current technologies, which technologies in existing PIV laboratories can be renewed, and which components are used in the PIV laboratories to be installed.

CFD Analysis of Sine Baffles on Flow Mixing and Power Consumption in Stirred Tank

In order to enhance the fluid mixing in the stirred tank and reduce the power consumption under the condition of full baffle, a sinusoidal sawtooth baffle was established in the present study. Based on the Eulerian–Eulerian method, a numerical simulation of the mixed flow in the stirred tank was conducted, and the reliability of the simulation method was verified by means of PIV experiments. The different structural characteristics of a standard baffle and the sine baffle were compared, to explore the effect of the modified baffle on flow mixing and power consumption in the tank. The outcomes indicate that the sinusoidal sawtooth structure had the effect of reducing drag and shunting, which could lessen the backflow on the backside of the baffle, strengthen the intensity of fluid turbulence and strain rate, improve the uniformity of particle distribution, and significantly lower the power consumption. When the relative tooth height was 0.333 and the relative tooth width was 0.028, the power consumption was reduced by 11.7%.

Investigation on the Flow Field and Mixing Efficiency of a Stirred Tank Equipped with Improved Intermig Impellers

The flow field in a transparent stirred tank with a diameter of D = 0.42 m equipped with dual-layer improved Intermig impellers was numerically investigated using a multi-reference frame method based on the computational fluid dynamics (CFD) simulation code: Fluent. The simulation results were validated by experiments based on a stirred tank testing platform and a Particle Image Velocimetry (PIV) testing instrument. The effects on the flow field arising from the diameter of impellers, the installation height of impellers (C1), the rotational speed as well as the distance between two impellers (C2) were investigated. It was revealed that the distance between two impellers and the installation height has obvious influences on the local flow field around impellers. Appropriately increasing the two parameters can enhance the axial flow and achieve a better mass transfer effect. For the tank model rescaled for experiments, the optimized geometrical parameters are C1 = 0.36D and C2 = 0.49D that can result in full occupation of large eddies in the entire volume. The mixing process simulation indicates that the mixing efficiency is the best in the region near the impellers while it is the worst in the bottom of the tank. An appropriate increase in the diameter of the lower impellers and a reduction in the distance from the lower impellers to the tank bottom can improve the mixing efficiency in the central region near the tank bottom.