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Karimzadeh M, Khatibi M, Ashrafizadeh SN, Mondal PK. Blue energy generation by the temperature-dependent properties in funnel-shaped soft nanochannels. Phys Chem Chem Phys 2022; 24:20303-20317. [PMID: 35979759 DOI: 10.1039/d2cp01015a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Salinity energy generation (SEG) studies have only been done under isothermal conditions at ambient temperature. The production of salinity energy can be improved under non-isothermal conditions, albeit preserving the energy efficiency. In the current study, the effects of gradients of temperature and concentration on the salinity energy generation process were examined simultaneously. Based on the temperature-dependent properties resulting from both temperature and concentration gradients, a numerical study was carried out to determine the maximum efficiency of salinity energy generation in funnel-shaped soft nanochannels. It was presumed that a dense layer of negative charge, called a polyelectrolyte layer (PEL), is coated on the walls of the nanochannels. Co-current and counter-current modes were used to obtain temperature and concentration gradients. Under steady-state conditions, the Poisson-Nernst-Planck, Stokes-Brinkman, and energy equations were numerically solved using equivalent approaches. The results revealed that by increasing the temperature and concentration ratios in both co-current and counter-current modes of operation, the salinity energy generation increased appreciably. The salinity energy generation increased from 30 to 80 pW upon increasing the temperature ratio from 1 to 8 at a constant concentration ratio of 1000 in counter-current mode. As verified from this analysis, low-grade heat sources (<100 °C) provide considerable energy conversion in PEL grafted nanofluidic confinement when placed between electrolyte solutions of different temperatures.
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Affiliation(s)
- Mohammad Karimzadeh
- Research Lab for Advanced Separation Processes, Department of Chemical Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran.
| | - Mahdi Khatibi
- Research Lab for Advanced Separation Processes, Department of Chemical Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran.
| | - Seyed Nezameddin Ashrafizadeh
- Research Lab for Advanced Separation Processes, Department of Chemical Engineering, Iran University of Science and Technology, Narmak, Tehran 16846-13114, Iran.
| | - Pranab Kumar Mondal
- Microfluidics and Microscale Transport Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Assam 781039, India.
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Rawat Y, Kalia S, Mondal PK. Quantitative model for predicting the imbibition dynamics of viscoelastic fluids in nonuniform microfluidic assays. Phys Rev E 2021; 104:055106. [PMID: 34942698 DOI: 10.1103/physreve.104.055106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 11/02/2021] [Indexed: 01/12/2023]
Abstract
We develop a mathematical model to quantitatively describe the imbibition dynamics of an elastic non-Newtonian fluid in a conical (nonuniform cross section) microfluidic assay. We consider the simplified Phan-Thien-Tanner viscoelastic model to represent the rheology of the elastic non-Newtonian fluid. Our model accounts for the geometrical features of the fluidic assay, the key parameters affecting the rheological behavior of the fluid, and predicts the imbibition dynamics effectively. By demonstrating the temporal advancement of the filling length in the conical capillary graphically, obtained for pertinent parametric values belonging to their physically permissible range, we report an underlying balance between capillary and viscous forces during imbibition resulting in three distinct regimes of filling. Nonuniformity in the capillary cross section gives rise to an alteration in the viscous force being applied at the contact line (manifested through the alteration in shear rate) during the imbibition process, which upon maintaining a balance with the dominant capillary force results in three different regimes of filling. We believe that the present analysis has a twofold significance. First, this work will enhance the understanding of underlying imbibition dynamics of viscoelastic fluids (most of the biofluids exhibit viscoelastic rheology) in nonuniform fluidic pathways. Second, the developed model is of significant practical relevance for the optimum design of microfluidic assays, primarily used for sample diagnostics in biochemical and biomedical applications.
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Affiliation(s)
- Yashwant Rawat
- Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Assam 781039, India
| | - Sachit Kalia
- Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Assam 781039, India
| | - Pranab Kumar Mondal
- Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Assam 781039, India
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Mondal PK, Roy M. Spreadsheet analysis of the field-driven start-up flow in a microfluidic channel. Electrophoresis 2021; 42:2465-2473. [PMID: 33856072 DOI: 10.1002/elps.202100038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 04/01/2021] [Accepted: 04/05/2021] [Indexed: 11/06/2022]
Abstract
We discuss, in this article, the solution method of the unsteady electroosmotic flow of Newtonian fluid in a square microfluidic channel cross-section in the framework of spreadsheet analysis. We demonstrate the implementation of the finite difference scheme, which is used for the discretization of the transport equations governing the flow dynamics of the present problem, in the spreadsheet tool. Also, we have shown the implementation details of different boundary conditions, which are typically used for the underlying electrohydrodynamics in a microfluidic channel, in the spreadsheet analysis tool. We show that the results obtained from the spreadsheet analysis match accurately with the numerical solutions for both the electrostatic potential distribution and the flow velocity. Our results of this analysis justify the credibility of the spreadsheet tool for capturing the intricate details of the electrically actuated microflows during the initial transiences, that is, for the start-up flows and the phenomenon due to the electrical double layer effect, quite effectively. The inferences of this analysis will open up a new research paradigm of microfluidics and microscale transport processes by providing the potential applicability of the spreadsheet tools to obtain the flow physics of our interest in a very intuitive and less expensive manner.
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Affiliation(s)
- Pranab Kumar Mondal
- Department of Mechanical Engineering, Microfluidics and Microscale Transport Processes Laboratory, Indian Institute of Technology Guwahati, Guwahati, India
| | - Manideep Roy
- Department of Mechanical Engineering, National Institute of Technology Durgapur, Durgapur, India
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Zhang L, Wu K, Chen Z, Li J, Yu X, Yang S, Hui G, Yang M. Quasi-Continuum Water Flow under Nanoconfined Conditions: Coupling the Effective Viscosity and the Slip Length. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.0c03507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Linyang Zhang
- Chemical and Petroleum Engineering, University of Calgary, Calgary, Alberta T2N1N4, Canada
| | - Keliu Wu
- State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China
| | - Zhangxin Chen
- Chemical and Petroleum Engineering, University of Calgary, Calgary, Alberta T2N1N4, Canada
- Key Laboratory for Petroleum Engineering of the Ministry of Education, China University of Petroleum (Beijing), Beijing 102249, China
| | - Jing Li
- Chemical and Petroleum Engineering, University of Calgary, Calgary, Alberta T2N1N4, Canada
- Key Laboratory for Petroleum Engineering of the Ministry of Education, China University of Petroleum (Beijing), Beijing 102249, China
| | - Xinran Yu
- Chemical and Petroleum Engineering, University of Calgary, Calgary, Alberta T2N1N4, Canada
| | - Sheng Yang
- Chemical and Petroleum Engineering, University of Calgary, Calgary, Alberta T2N1N4, Canada
| | - Gang Hui
- Chemical and Petroleum Engineering, University of Calgary, Calgary, Alberta T2N1N4, Canada
| | - Min Yang
- Chemical and Petroleum Engineering, University of Calgary, Calgary, Alberta T2N1N4, Canada
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Gorthi SR, Meher SK, Biswas G, Mondal PK. Capillary imbibition of non-Newtonian fluids in a microfluidic channel: analysis and experiments. Proc Math Phys Eng Sci 2020. [DOI: 10.1098/rspa.2020.0496] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
We have presented an experimental analysis on the investigations of capillary filling dynamics of inelastic non-Newtonian fluids in the regime of surface tension dominated flows. We use the Ostwald–de Waele power-law model to describe the rheology of the non-Newtonian fluids. Our analysis primarily focuses on the experimental observations and revisits the theoretical understanding of the capillary dynamics from the perspective of filling kinematics at the interfacial scale. Notably, theoretical predictions of the filling length into the capillary largely endorse our experimental results. We study the effects of the shear-thinning nature of the fluid on the underlying filling phenomenon in the capillary-driven regime through a quantitative analysis. We further show that the dynamics of contact line motion in this regime plays an essential role in advancing the fluid front in the capillary. Our experimental results on the filling in a horizontal capillary re-establish the applicability of the Washburn analysis in predicting the filling characteristics of non-Newtonian fluids in a vertical capillary during early stage of filling (Digilov 2008
Langmuir
24
, 13 663–13 667 (
doi:10.1021/la801807j
)). Finally, through a scaling analysis, we suggest that the late stage of filling by the shear-thinning fluids closely follows the variation
x
~
t
. Such a regime can be called the modified Washburn regime (Washburn 1921
Phys. Rev.
17
, 273–283 (
doi:10.1103/PhysRev.17.273
)).
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Affiliation(s)
- Srinivas R. Gorthi
- Microfluidics and Microscale Transport Processes Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
| | - Sanjaya Kumar Meher
- Microfluidics and Microscale Transport Processes Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
| | - Gautam Biswas
- Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Pranab Kumar Mondal
- Microfluidics and Microscale Transport Processes Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
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Gaikwad HS, Kumar G, Mondal PK. Efficient electroosmotic mixing in a narrow-fluidic channel: the role of a patterned soft layer. SOFT MATTER 2020; 16:6304-6316. [PMID: 32572423 DOI: 10.1039/d0sm00890g] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We propose a novel and efficient mixing technique in a soft narrow-fluidic channel under the influence of electrical forcing. We show that a grafted polyelectrolyte layer (PEL) added as a patch to the channel wall modulates the electrical double layer (EDL) so that an applied electric field initiates a local electroosmotic flow (EOF) at the patched section. This EOF develops in the opposite direction to the primary pressure-driven flow. This localized EOF leads to the formation of Lamb vortices at the patched sections through the phenomenon of momentum exchange with the primary stream and promotes the mixing therein. Our study, consistent with the stream-function/vorticity approach, primarily focuses on the numerical analysis of the mixing phenomena. Through a quantitative description, we reveal the effect of different patterns on the underlying mixing phenomena in the convective mixing regime. We also discuss the impact of key parameters on the mixing efficiency, the onset of the recirculation zone, variation in the mixing length, and the shear-driven aggregation kinetics in soft matter systems. Finally, considering the practicability of the present problem, we unveil the values of several design parameters for which the mixing efficiency in the channel reaches the maximum.
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Affiliation(s)
- Harshad Sanjay Gaikwad
- Microfluidics and Microscale Transport Processes Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Assam 781039, India.
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Nigam KDP, Ranade VV. I&EC Research Special Issue on Fluidic Devices without Moving Parts. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.0c00710] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- K. D. P. Nigam
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, India
- Tecnologico de Monterrey, Monterrey, Nuevo León 64849, Mexico
| | - Vivek V. Ranade
- Bernal Institute, University of Limerick, Limerick, Ireland
- School of Chemistry and Chemical Engineering, Queen’s University Belfast, Belfast, United Kingdom
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