Pressure-flow characteristics of a microchannel combining super-hydrophobicity and wall compliance

IF 2.3 4区 工程技术 Q2 INSTRUMENTS & INSTRUMENTATION
Kumar Amit, Ashwani Assam, Abhishek Raj
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引用次数: 0

Abstract

Drag is a major concern in microfluidic devices impacting flow stability, energy efficiency, and fluid flow control. Minimizing drag enhances performance and efficiency in various applications, such as flow stabilization microdevices, microvalves, and micropumps. Often, superhydrophobicity is utilized for drag-reduction applications. However, superhydrophobic surfaces tend to fail at higher Reynolds numbers. This paper investigates the pressure-flow characteristics of a microchannel having a superhydrophobic bottom wall with embedded air-cavities, and a deformable top membrane, both numerically and theoretically. The aim is to understand fluid flows in the deformable superhydrophobic microchannel and leverage its water-repellent property and deformability both together to reduce drag while maintaining the durability of the superhydrophobic wall. Two-way fluid–structure interaction (FSI) and unsteady volume of fluid (VOF) methods are employed for fluid–solid boundary and liquid–air interface at ridge-cavity, respectively. A novel theoretical model has been developed for the pressure-flow characteristics of a microchannel with a deformable top and superhydrophobic bottom wall. The theoretical and numerical results for pressure drop across the microchannel have shown a good agreement with a maximum deviation of 6.69%. Four distinct types of microchannels viz, smooth (S) (rigid non-textured), smooth with deformable top (SDT), smooth with superhydrophobic bottom (SSB), and smooth with superhydrophobic bottom and deformable top wall (SSBDT) have been investigated for the comparison of their pressure-flow characteristics. The Poiseuille Number (fRe) for SSBDT microchannel is found to be lowest with an average of 18.7% and a maximum of 23.5% lower than S microchannel at Re = 60. Up to 48.59% of reduction in pressure drop was observed for the SSBDT microchannel as compared to smooth (S) microchannel of the same dimensions. Furthermore, critical Reynolds Number (Recritical) (at which the air–water interface breaks and super-hydrophobicity vanishes) was found to be ~ 20% higher for the SSBDT microchannel compared to the SSB microchannel. Thus, the wall compliance in the SSBDT microchannel is found to increase the capability to sustain the super-hydrophobicity at higher Re numbers. The proposed approach for drag reduction in microchannel can be vital to enhance the efficiency and capability of numerous microdevices needing high Reynolds number flows, such as high throughput cell sorters, microvalves, and micropumps.

Abstract Image

结合超疏水性和壁顺性的微通道的压力流动特性
在微流体装置中,阻力是影响流动稳定性、能量效率和流体流动控制的主要问题。最小化阻力可提高各种应用的性能和效率,如流量稳定微装置、微阀和微泵。通常,超疏水性用于减阻应用。然而,超疏水表面往往在高雷诺数下失效。本文从数值和理论两方面研究了具有超疏水底壁嵌入空腔和可变形顶膜的微通道的压力流动特性。目的是了解可变形超疏水微通道中的流体流动情况,并利用其拒水性和可变形性来减少阻力,同时保持超疏水壁的耐久性。采用双向流固耦合法(FSI)和非定常体积法(VOF)分别计算了脊腔处的流固边界和液气界面。建立了一种具有可变形顶壁和超疏水底壁的微通道压力流动特性的新理论模型。微通道压降的理论计算结果与数值计算结果一致,最大偏差为6.69%。研究了四种不同类型的微通道,即光滑(S)(刚性无纹理)、顶部可变形光滑(SDT)、底部超疏水光滑(SSB)、底部超疏水光滑和顶部可变形壁面光滑(SSBDT),并对其压力流动特性进行了比较。在Re = 60时,SSBDT微通道的泊泽维尔数(Poiseuille Number, fRe)平均比S微通道低18.7%,最大比S微通道低23.5%。与相同尺寸的光滑(S)微通道相比,SSBDT微通道的压降降低了48.59%。此外,与SSB微通道相比,SSBDT微通道的临界雷诺数(临界雷诺数,即空气-水界面破裂和超疏水性消失)高出约20%。因此,发现SSBDT微通道的壁顺性增加了在较高Re数下维持超疏水性的能力。所提出的减少微通道阻力的方法对于提高许多需要高雷诺数流的微设备的效率和能力至关重要,例如高通量细胞分选器、微阀和微泵。
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
Microfluidics and Nanofluidics
Microfluidics and Nanofluidics 工程技术-纳米科技
CiteScore
4.80
自引率
3.60%
发文量
97
审稿时长
2 months
期刊介绍: Microfluidics and Nanofluidics is an international peer-reviewed journal that aims to publish papers in all aspects of microfluidics, nanofluidics and lab-on-a-chip science and technology. The objectives of the journal are to (1) provide an overview of the current state of the research and development in microfluidics, nanofluidics and lab-on-a-chip devices, (2) improve the fundamental understanding of microfluidic and nanofluidic phenomena, and (3) discuss applications of microfluidics, nanofluidics and lab-on-a-chip devices. Topics covered in this journal include: 1.000 Fundamental principles of micro- and nanoscale phenomena like, flow, mass transport and reactions 3.000 Theoretical models and numerical simulation with experimental and/or analytical proof 4.000 Novel measurement & characterization technologies 5.000 Devices (actuators and sensors) 6.000 New unit-operations for dedicated microfluidic platforms 7.000 Lab-on-a-Chip applications 8.000 Microfabrication technologies and materials Please note, Microfluidics and Nanofluidics does not publish manuscripts studying pure microscale heat transfer since there are many journals that cover this field of research (Journal of Heat Transfer, Journal of Heat and Mass Transfer, Journal of Heat and Fluid Flow, etc.).
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