Mechanism of the Absent Air Column in Three Products Hydrocyclone Screen (TPHS): Experiment and Simulation

Chuanzhen Wang,Md Shakhaoath Khan,Haizeng Liu,Zaisheng Zhu,Anghong Yu

doi:10.3390/pr9030431

Chuanzhen Wang, Md Shakhaoath Khan + Show 3 more

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https://doi.org/10.3390/pr9030431

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Abstract

Three products hyrdrocyclone screen (TPHS) has been proposed for particle separation based on size. In TPHS, a cylindrical screen was embedded in a conventional hydrocyclone (CH) to combine the centrifugal classification and screening to particle separation based on size. The industrial application of TPHS indicates its better device performance than CH. Although, the earlier studies reveal some common understanding for TPHS, the information of the absent air column remains unknown. Hence, the combination of physical experiment and numerical simulation was considered involving a 75 mm TPHS for this knowledge gap. First, both the computational fluid dynamics (CFD) simulation with Reynolds stress mode and the physical experiment with a high-definition camera illustrate the development process details of a flow field in TPHS. That is, the water was imported along the tangential inlet into TPHS; then under the effects of the feed chamber wall and gravity, the liquid phase spiraled downward until the cylindrical screen passed through the sieve; as the liquid moved to the spigot, it could be discharged in time due to the small underflow port, thus the volume fraction of air rapidly reduced from 1 to 0; subsequently the water filled the TPHS and the absent air column could be observed. Furthermore, the distribution comparisons of air volume fraction and static pressure show that TPHS displayed the absent air core with the negative static pressure in the center region along the z-axis, while CH displayed the opposite features. In addition, despite the different inlet velocity, TPHS consistently presented the vanished air column which could be ascribed to the fact that the present cylindrical screen resulted in positive static pressure distribution inside TPHS.

Highlights

Cyclones are generally known as essential particle separation devices in the centrifugal force field [1]
The three products hydrocyclone screen (TPHS), which has a cylindrical screen embedded in a conventional hydrocyclone (CH), has been successfully investigated
Both the computational fluid dynamics (CFD) simulation with the Reynolds stress model (RSM) model and the physical experiment with a highdefinition camera were adopted involving a 75 mm TPHS to research the details of the absent air column inside this cyclone

Summary

Introduction

Cyclones are generally known as essential particle separation devices in the centrifugal force field [1]. A JK (the abbreviation of Julius Kruttschnitt Mineral Research Centre) three-product cyclone is characterized by a second vortex finer to produce a second overflow in which the fine dense liberated particles can be selectively concentrated for further treatment [6]; or using a filtering cyclone by incorporating a permeable cone into a cyclone with a conventional structure [7]. A JK (the abbreviation of Julius Kruttschnitt Mineral Research Centre) three-product cyclone is characterized by a second vortex finer to produce a second overflow in which the fine dense liberated particles can be selectively concentrated for further treatment [6]; or using a filtering cyclone by incorporating a permeable cone into a cyclone with a conventional structure [7]. 4.0/).

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