Turbulent impingement jet cleaning of thick viscoplastic layers

IF 2.7 2区工程技术 Q2 MECHANICS

Journal of Non-Newtonian Fluid Mechanics Pub Date : 2024-06-05 DOI:10.1016/j.jnnfm.2024.105264

H. Hassanzadeh , D.I. Wilson , I.A. Frigaard , S.M. Taghavi

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Abstract

An experimental study is conducted on the use of a normally impinging turbulent water jet (with the Reynolds number of $R e \approx 11 800$ ), for cleaning thick layers of a Newtonian fluid and two viscoplastic fluids (i.e., transparent Carbopol solutions). The layer thickness is larger than the jet radius. Non-intrusive techniques are used to track the geometrical features of the cleaning process in real time. The effects of layer thickness and fluid yield stress on removal behavior, including cleaning radius, cavity radius, and angle, are investigated. A yield stress promotes the initial formation of a blister rather than a cavity, and the rate of removal decreases with increasing layer thickness and yield stress. A relation is presented for the growth of the cavity radius, which fits our experimental observations well. A comparative analysis of submerged and impinging jets reveals, for the first time, the role of air entrainment in the process, with bubble characteristics such as trajectory, size distribution (diameter), and velocity being determined by the yield stress.

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厚粘塑性层的湍流撞击射流清洗

我们进行了一项实验研究，利用正常冲击湍流水射流（雷诺数为 Re≈11800）清洗牛顿流体和两种粘性流体（即透明的 Carbopol 溶液）的厚层。层厚度大于喷射半径。采用非侵入式技术实时跟踪清洗过程的几何特征。研究了清洗层厚度和流体屈服应力对清洗行为的影响，包括清洗半径、空腔半径和角度。屈服应力会促进水泡而非空腔的初步形成，而且随着层厚度和屈服应力的增加，清除率也会降低。研究还提出了空腔半径的增长关系，这与我们的实验观察结果十分吻合。对浸没式和撞击式喷流的比较分析首次揭示了空气夹带在这一过程中的作用，气泡的轨迹、大小分布（直径）和速度等特征由屈服应力决定。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Non-Newtonian Fluid Mechanics 物理-力学

CiteScore

5.00

自引率

19.40%

发文量

109

审稿时长

61 days

期刊介绍： The Journal of Non-Newtonian Fluid Mechanics publishes research on flowing soft matter systems. Submissions in all areas of flowing complex fluids are welcomed, including polymer melts and solutions, suspensions, colloids, surfactant solutions, biological fluids, gels, liquid crystals and granular materials. Flow problems relevant to microfluidics, lab-on-a-chip, nanofluidics, biological flows, geophysical flows, industrial processes and other applications are of interest. Subjects considered suitable for the journal include the following (not necessarily in order of importance): Theoretical, computational and experimental studies of naturally or technologically relevant flow problems where the non-Newtonian nature of the fluid is important in determining the character of the flow. We seek in particular studies that lend mechanistic insight into flow behavior in complex fluids or highlight flow phenomena unique to complex fluids. Examples include Instabilities, unsteady and turbulent or chaotic flow characteristics in non-Newtonian fluids, Multiphase flows involving complex fluids, Problems involving transport phenomena such as heat and mass transfer and mixing, to the extent that the non-Newtonian flow behavior is central to the transport phenomena, Novel flow situations that suggest the need for further theoretical study, Practical situations of flow that are in need of systematic theoretical and experimental research. Such issues and developments commonly arise, for example, in the polymer processing, petroleum, pharmaceutical, biomedical and consumer product industries.