Impact of inlet flow rate on dynamic liquid film thickness and flow stability in spiral concentrator

IF 4.6 2区工程技术 Q2 ENGINEERING, CHEMICAL

Powder Technology Pub Date : 2025-07-26 DOI:10.1016/j.powtec.2025.121472

Huizhong Liu , Jian Wang

{"title":"Impact of inlet flow rate on dynamic liquid film thickness and flow stability in spiral concentrator","authors":"Huizhong Liu , Jian Wang","doi":"10.1016/j.powtec.2025.121472","DOIUrl":null,"url":null,"abstract":"<div><div>The dynamic behavior of liquid films, particularly thickness variations, critically governs separation efficiency in spiral concentrators. During operation, flow instabilities in specific concentrator designs trigger periodic rolling waves that significantly alter hydrodynamic characteristics and particle transport. Notably, this phenomenon remains underexplored in mineral processing research. Through integrated experimental and computational fluid dynamics (CFD) simulations, we systematically investigated rolling wave dynamics in industrial-scale spiral concentrators. Our findings demonstrate that wave morphology correlates with trough geometry, surface flow regimes, and particle transport characteristics at the base. Inlet flow rate (Q) emerged as a pivotal control parameter: at Q = 9 L/min, waves exhibited maximum amplitude but minimal frequency and stability; Q = 11 L/min yielded optimal waveform stability; while Q = 13 L/min generated peak Froude numbers (<em>Fr</em> ≈ 2.83), following a unimodal trend mirroring wave height evolution. Crucially, periodic waves modulate near-wall shear rates, inducing Bagnold force fluctuations that govern particle loosening. Elevated velocity gradients at Q = 9/13 L/min promoted significant particle agitation and segregation through ±38 % Bagnold force variations, whereas stabilized shear rates at Q = 11 L/min enabled uniform particle flow. This study offers significant insights into the distribution and motion characteristics of particles under rolling wave conditions.</div></div>","PeriodicalId":407,"journal":{"name":"Powder Technology","volume":"466 ","pages":"Article 121472"},"PeriodicalIF":4.6000,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Powder Technology","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0032591025008678","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}

引用次数: 0

Abstract

The dynamic behavior of liquid films, particularly thickness variations, critically governs separation efficiency in spiral concentrators. During operation, flow instabilities in specific concentrator designs trigger periodic rolling waves that significantly alter hydrodynamic characteristics and particle transport. Notably, this phenomenon remains underexplored in mineral processing research. Through integrated experimental and computational fluid dynamics (CFD) simulations, we systematically investigated rolling wave dynamics in industrial-scale spiral concentrators. Our findings demonstrate that wave morphology correlates with trough geometry, surface flow regimes, and particle transport characteristics at the base. Inlet flow rate (Q) emerged as a pivotal control parameter: at Q = 9 L/min, waves exhibited maximum amplitude but minimal frequency and stability; Q = 11 L/min yielded optimal waveform stability; while Q = 13 L/min generated peak Froude numbers (Fr ≈ 2.83), following a unimodal trend mirroring wave height evolution. Crucially, periodic waves modulate near-wall shear rates, inducing Bagnold force fluctuations that govern particle loosening. Elevated velocity gradients at Q = 9/13 L/min promoted significant particle agitation and segregation through ±38 % Bagnold force variations, whereas stabilized shear rates at Q = 11 L/min enabled uniform particle flow. This study offers significant insights into the distribution and motion characteristics of particles under rolling wave conditions.

Abstract Image

查看原文本刊更多论文

进口流量对螺旋选矿厂动态液膜厚度及流动稳定性的影响

液膜的动态特性，特别是厚度的变化，对螺旋选矿厂的分离效率起着至关重要的作用。在运行过程中，特定浓缩器设计中的流动不稳定会触发周期性的滚动波，从而显著改变流体动力特性和颗粒输运。值得注意的是，这一现象在矿物加工研究中仍未得到充分探讨。通过综合实验和计算流体动力学（CFD）模拟，系统地研究了工业规模螺旋选矿厂的滚波动力学。我们的研究结果表明，波浪形态与槽的几何形状、表面流态和底部的颗粒输运特征有关。进口流量(Q)成为关键的控制参数：当Q = 9 L/min时，波浪的幅值最大，频率最小，且稳定；Q = 11 L/min，波形稳定性最佳；当Q = 13 L/min时，产生峰值弗鲁德数（Fr≈2.83），呈反映波高演变的单峰趋势。至关重要的是，周期波调节近壁剪切速率，引起控制颗粒松动的巴格诺力波动。速度梯度在Q = 9/13 L/min时，通过±38%的巴格诺力变化促进了显著的颗粒搅拌和偏析，而稳定的剪切速率在Q = 11 L/min时，使颗粒均匀流动。该研究对滚波条件下粒子的分布和运动特性提供了重要的见解。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Powder Technology 工程技术-工程：化工

CiteScore

9.90

自引率

15.40%

发文量

1047

审稿时长

46 days

期刊介绍： Powder Technology is an International Journal on the Science and Technology of Wet and Dry Particulate Systems. Powder Technology publishes papers on all aspects of the formation of particles and their characterisation and on the study of systems containing particulate solids. No limitation is imposed on the size of the particles, which may range from nanometre scale, as in pigments or aerosols, to that of mined or quarried materials. The following list of topics is not intended to be comprehensive, but rather to indicate typical subjects which fall within the scope of the journal's interests: Formation and synthesis of particles by precipitation and other methods. Modification of particles by agglomeration, coating, comminution and attrition. Characterisation of the size, shape, surface area, pore structure and strength of particles and agglomerates (including the origins and effects of inter particle forces). Packing, failure, flow and permeability of assemblies of particles. Particle-particle interactions and suspension rheology. Handling and processing operations such as slurry flow, fluidization, pneumatic conveying. Interactions between particles and their environment, including delivery of particulate products to the body. Applications of particle technology in production of pharmaceuticals, chemicals, foods, pigments, structural, and functional materials and in environmental and energy related matters. For materials-oriented contributions we are looking for articles revealing the effect of particle/powder characteristics (size, morphology and composition, in that order) on material performance or functionality and, ideally, comparison to any industrial standard.