Experimental study on the air core in a hydrocyclone

Zou, Jun; Wang, Chenxiang; Chen, Ji

doi:10.1080/07373937.2015.1046554

Cited by 25 publications

(4 citation statements)

References 28 publications

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“…Furthermore, TPHS presents an interesting phenomenon, namely the absent air column. The previous investigations also indicate that the occurrence of an air column drastically reduces the efficiency of separation [17,18], which can be attributed to the fact that the air core could lead to more energy consumption and ineffective particle separation, and thus some efforts were considered to eliminate the air core for better device performance [19][20][21]. Since TPHS can be considered as one kind of cyclone, the absent air core should promote particle separation [16].…”

Section: Experimental Facilitiesmentioning

confidence: 99%

“…During the operation of the CH separators, the air column is generally considered as having flow characteristics which largely affect the device's performance [20,27]. The formation of air core can be attributed to the pressure drop which leads to the negative pressure region in the center of cyclone, i.e., the pressure difference the axial center of the hydrocyclone and the atmospheric pressure [17,20,28,29]. Hence, the air can be sucked through the outlets (in the open-to-air cyclone) [30,31] or released from the dissolved gas brought in from the feed inlet (in the sealed-air cyclone) [20,31] to create the air core.…”

Section: Mechanism Of the Absent Air Column In Tphsmentioning

confidence: 99%

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

Wang

Zhu

et al. 2021

Processes

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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.

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Section: Experimental Facilitiesmentioning

confidence: 99%

Section: Mechanism Of the Absent Air Column In Tphsmentioning

confidence: 99%

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

Wang

Zhu

et al. 2021

Processes

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“…When measuring different flow field parameters, various structural components must be manufactured and different measurement methods must be performed. The labor, material, and time costs are huge [22][23][24]. With technological progress, CFD has become a powerful method for the simulation of complex flow phenomena.…”

Section: Introductionmentioning

confidence: 99%

Effect of Overflow Pipe on the Internal Flow Fields and Separation Performance of W-Shaped Hydrocyclones

et al. 2020

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The entrainment of fine particles in underflow of a grinding-classification hydrocyclone can cause ore overgrinding, which will lead to reductions in both metal recovery and ball mill throughput. To address this problem, this paper proposed a W-shaped hydrocyclone that can effectively reduce underflow fine particle entrainment. Experimental tests and numerical simulations were employed to deeply investigate overflow pipe diameter influence on the separation performance and internal flow field of W-shaped hydrocyclones. The effects of overflow pipe diameter on air core shape, velocity field, pressure field, and separation performance were studied. The results revealed that as the diameter of the overflow pipe increased, air core gradually stabilized, and air core diameter gradually increased. The diameter of stabilized air core was approximately 45% to 55% of overflow pipe diameter. As overflow pipe diameter increased, hydrocyclone pressure drop decreased, energy consumption was reduced, the tangential velocity decreased, outer vortex axial velocity did not change significantly, and inner vortex axial velocity gradually increased. At the same time, zero-velocity points gradually moved outward, and the inner vortex region expanded. By the increase of overflow pipe diameter, both the underflow yield and split ratio gradually decreased, the coarse particle content in the overflow product increased, and the fine particle content in the underflow product gradually decreased.

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“…In terms of the optimization of the structural parameters of the hydrocyclone, the representative studies include experimental studies on the hydrocyclone column height and diameter [14,15], feed inlet type and size [16,17], overflow pipe diameter, length, and shape, overflow pipe thickness [18][19][20], underflow outlet diameter, and shape, ratio relationship between the underflow outlet and overflow outlet [21][22][23]. A series of new hydrocyclone types have been designed, such as the built-in structural hydrocyclone [24,25], underflow outlet filled with flushing water [26], multi-stage series or parallel hydrocyclone [27][28][29], and three-product cyclone [30,31]. Mainza is one of the earliest researchers who put forward the three-product hydrocyclone, and the three-product hydrocyclone has been successfully tested in the Platinum industry for classifying UG2 ore which contains a high density chromite and a low density PGM carrying silica component.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Flow Field Characteristics and Separation Performance Test of Multi-Product Hydrocyclone

et al. 2019

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A traditional hydrocyclone can only generate two products with different size fractions after one classification, which does not meet the fine classification requirements for narrow size fractions. In order to achieve the fine classification, a multi-product hydrocyclone with double-overflow-pipe structure was designed in this study. In this work, numerical simulation and experimental test methods were used to study the internal flow field characteristics and distribution characteristics of the product size fraction. The simulation results showed that in contrast with the traditional single overflow pipe, there were two turns in the internal axial velocity direction of the hydrocyclone with the double-overflow-pipe structure. Meanwhile, the influence rule of the diameter of the underflow outlet on the flow field characteristics was obtained through numerical simulation. From the test, five products with different size fractions were obtained after one classification and the influence rule of the diameter of the underflow outlet on the size fraction distribution of multi-products was also obtained. This work provides a feasible research idea for obtaining the fine classification of multiple products.

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Experimental study on the air core in a hydrocyclone

Cited by 25 publications

References 28 publications

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

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

Effect of Overflow Pipe on the Internal Flow Fields and Separation Performance of W-Shaped Hydrocyclones

Numerical Simulation of Flow Field Characteristics and Separation Performance Test of Multi-Product Hydrocyclone

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