The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Pranab Kumar Mondal - One of the best experts on this subject based on the ideXlab platform.
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Analysis of the Effects of Joule Heating and Viscous Dissipation on Combined Pressure-Driven and Electrokinetic Flows in a Two-Parallel Plate Channel with Unequal Constant Temperatures:
Proceedings of the Institution of Mechanical Engineers Part E: Journal of Process Mechanical Engineering, 2018Co-Authors: Harshad Sanjay Gaikwad, Pranab Kumar Mondal, Dipankar N Basu, Nares Chimres, Somchai WongwisesAbstract:In this article, we perform an entropy generation analysis for the micro channel heat sink applications where the flow of fluid is actuated by combined influences of Applied Pressure Gradient and e...
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Effect of thermal asymmetries on the entropy generation analysis of a variable viscosity Couette–Poiseuille flow
Proceedings of the Institution of Mechanical Engineers Part E: Journal of Process Mechanical Engineering, 2017Co-Authors: Pranab Kumar Mondal, Harshad Sanjay Gaikwad, Pranab Kumar Kundu, Somchai WongwisesAbstract:The influence of viscous dissipation on forced convective heat transfer and entropy generation rate in the conduction limit for a variable-viscosity flow between asymmetrically heated parallel plates is studied in an analytical framework consistent with perturbation method. The study considers a flow of Newtonian fluid under the simultaneous action of an Applied Pressure Gradient and an axial movement of the upper plate. The present study emphasizes on the effect of dissipative heat produced by the movable upper plate as well as viscous heating generated due to Applied Pressure Gradient on the underlying thermo-hydrodynamic transport. A few non-dimensional parameters such as dimensionless upper plate velocity, degree of asymmetry parameter and Brinkman number have been defined and their influential role on the variation of temperature profile, the Nusselt number and entropy generation number has been discussed in detail. The study shows that the variation of Nusselt number exhibits an unbounded swing, which, in turn, leads to appearance of the point of singularities at some cases of asymmetrical plate heating. Finally, the source of appearance of point of singularities has been discussed in view of the energy balance, and from the second-law analysis of thermodynamics.
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electroosmotic transport of immiscible binary system with a layer of non conducting fluid under interfacial slip the role Applied Pressure Gradient
Electrophoresis, 2016Co-Authors: Harshad Sanjay Gaikwad, Dipankar N Basu, Pranab Kumar MondalAbstract:We investigate the transport of immiscible binary fluid layers, constituted by one conducting (top layer fluid) and another non-conducting (bottom layer fluid) fluids in a microfluidic channel under the combined influences of an Applied Pressure Gradient and imposed electric field. We solve the transport equation governing the flow dynamics analytically and obtain the closed-form expressions of the velocity fields. We bring out the alteration in the flow dynamics, mainly attributable to the non-linear interaction between interfacial slip and the electrical double layer effect over small scales as modulated by the Applied Pressure Gradient. In particular, we show the augmentation in the net volume transport rate through the channel, emerging from an intricate competition among electrical forcing, Applied Pressure Gradient and the viscous resistance as modulated by the interfacial slip. We believe that the results of this study may be of immense consequence for the design of various microfluidic devises, which are often used for the manipulation of two immiscible fluids in different biomedical/biochemical processes.
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effect of conjugate heat transfer on the irreversibility generation rate in a combined couette poiseuille flow between asymmetrically heated parallel plates the entropy minimization analysis
Energy, 2015Co-Authors: Pranab Kumar Mondal, Shibdas DholeyAbstract:We investigate the entropy transport dynamics of a Newtonian fluid in a parallel-plate channel considering the effect of conjugate heat transfer into the analysis. We consider that the flow to be actuated by the combined influences of externally Applied Pressure Gradient and movement of the upper plate of the channel. Using an analytical scheme associated with the thermal boundary conditions of third kind at the outer boundaries of the channel, we bring out the alteration in the underlying thermal transport characteristics of heat as attributable to the nonlinear interactions between flow dynamics and viscous heating. Our analysis demonstrates the influential role of different performance index parameters viz., the geometric parameters, material properties, flow conditions on the irreversibility generation rate of the system. In particular, we unveil an optimum value of wall thickness and wall to fluid conductivity ratio that leads to minimization of the entropy generation rate in the system owing to intricate interplay between the heat flow dynamics and viscous heating. Our results may have far ranging consequences in the design of various cooling and heat removal devices and systems, which are often used in different engineering applications.
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Entropy analysis for the Couette flow of non-Newtonian fluids between asymmetrically heated parallel plates: effect of Applied Pressure Gradient
Physica Scripta, 2014Co-Authors: Pranab Kumar MondalAbstract:The current study discusses the irreversibility analysis for the Couette flow of non-Newtonian fluids between two asymmetrically heated parallel plates for two different flow configurations viz., under the application of a weak Pressure Gradient and for a relatively strong Pressure Gradient. The plates are kept at different constant temperatures, while the effect of viscous dissipation is included in the analysis. The study explores the combined consequences of the rheological effect of the fluids, the movement of the upper plate, and the magnitude of the externally Applied Pressure Gradient on the irreversibility generation rate of the system as manifested by the variation of the volumetric entropy generation number, irreversibility distribution ratio, and the Bejan number. Intricate interplay between the effects of fluid friction and heat transfer in dictating the irreversibility of the system is highlighted for different degrees of asymmetrical wall heating and upper-plate velocity. The study further shows that, for a given degree of asymmetrical wall heating, the irreversibility generation rate alters with the alteration in the rheological behaviour of the fluid.
Olga I. Vinogradova - One of the best experts on this subject based on the ideXlab platform.
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Principles of transverse flow fractionation of microparticles in superhydrophobic channels.
Lab on a chip, 2015Co-Authors: Evgeny S. Asmolov, Alexander L. Dubov, Tatiana V. Nizkaya, Alexander J. C. Kuehne, Olga I. VinogradovaAbstract:We propose a concept of fractionation of micron-sized particles in a microfluidic device with a bottom wall decorated by superhydrophobic stripes. The stripes are oriented at an angle α to the direction of a driving force, G, which generally includes an Applied Pressure Gradient and gravity. Separation relies on the initial sedimentation of particles under gravity in the main forward flow, and their subsequent lateral deflection near a superhydrophobic wall due to generation of a secondary flow transverse to G. We provide some theoretical arguments allowing us to quantify the transverse displacement of particles in the microfluidic channel, and confirm the validity of theoretical predictions in test experiments with monodisperse fractions of microparticles. Our results can guide the design of superhydrophobic microfluidic devices for efficient sorting of microparticles with a relatively small difference in size and density.
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Flows and mixing in channels with misaligned superhydrophobic walls.
Physical review. E Statistical nonlinear and soft matter physics, 2015Co-Authors: Tatiana V. Nizkaya, Evgeny S. Asmolov, Jiajia Zhou, Friederike Schmid, Olga I. VinogradovaAbstract:Aligned superhydrophobic surfaces with the same texture orientation reduce drag in the channel and generate secondary flows transverse to the direction of the Applied Pressure Gradient. Here we show that a transverse shear can be easily generated by using superhydrophobic channels with misaligned textured surfaces. We propose a general theoretical approach to quantify this transverse flow by introducing the concept of an effective shear tensor. To illustrate its use, we present approximate theoretical solutions and Dissipative Particle Dynamics simulations for striped superhydrophobic channels. Our results demonstrate that the transverse shear leads to complex flow patterns, which provide a new mechanism of a passive vertical mixing at the scale of a texture period. Depending on the value of Reynolds number two different scenarios occur. At relatively low Reynolds number the flow represents a transverse shear superimposed with two corotating vortices. For larger Reynolds number these vortices become isolated, by suppressing fluid transport in the transverse direction.
Jyh-ping Hsu - One of the best experts on this subject based on the ideXlab platform.
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Nanopore-based desalination subject to simultaneously Applied Pressure Gradient and gating potential
Journal of colloid and interface science, 2021Co-Authors: Chia-yang Chung, Jyh-ping HsuAbstract:Abstract The performance of a dielectric membrane in desalting is assessed by considering a cylindrical nanopore, surface modified by a dielectric layer, subject to simultaneously Applied Pressure Gradient and gating potential. The charged conditions of the nanopore can be tuned by modulating the Applied gating potential so that it can be used for rejecting different types of salt. In general, the thinner the dielectric layer and/or the larger its dielectric constant the better the salt rejection performance. For example, if the thickness of the dielectric layer is 10 nm with a relative dielectric constant of 25, applying a Pressure difference of 5 MPa and gating potential of 1 V yields 49 % rejection. However, it declines to 9 % if the relative dielectric constant is lowered to 5 with other parameters fixed, and 23 % if that thickness is 50 nm with other parameters fixed. The results of numerical simulation based on various types of single salt and mixture salts with ions of different valences reveal that the type of ions which need be filtrated can be selected effectively through regulating the gating potential.
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Residence time distribution for electrokinetic flow through a microchannel comprising a bundle of cylinders.
Journal of colloid and interface science, 2006Co-Authors: Jyh-ping Hsu, Chung-chieh Ting, Duu-jong Lee, Shiojenn Tseng, Chur-jen ChenAbstract:The electrokinetic flow of an electrolyte solution through a microchannel that comprises a bundle of cylinders is investigated for the case of constant surface potential. The system under consideration is simulated by a unit cell model, and analytical expressions for the flow field and the corresponding residence time distribution under various conditions are derived. These results are readily applicable to the assessment of the performance of a microreactor such as that which comprises a bundle of optical fibers. Numerical simulations are conducted to investigate the influences of the key parameters, including the thickness of the double layer, the strength of the Applied electric field, the magnitude of the Applied Pressure Gradient, and the characteristic sizes of a microchannel, on the residence time distribution. We show that the following could result in a shorter residence time: thin double layer, strong Applied electric field, large Applied Pressure Gradient, and small number of cylinders. Based on the thickness of the double layer, criteria are proposed for whether the flow field can be treated as a laminar flow or as a plug flow, two basic limiting cases in reactor design.
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Residence time distribution of a cylindrical microreactor.
The journal of physical chemistry. B, 2005Co-Authors: Jyh-ping Hsu, Tzu-hsuan WeiAbstract:The residence time distribution for the flow of liquid reactants containing electrolytes in a cylindrical microreactor is derived under the conditions of constant surface potential and negligible end effects. The influences of the key parameters, including the thickness of the double layer, the strength of the Applied electric field, and the magnitude of the Applied Pressure Gradient, on the behavior of residence time distribution are discussed. The results obtained provide necessary information for the design and optimization of microreactors which involve liquid electrolyte reactants. The results of the numerical simulation reveal that a thin double layer, a strong Applied electric field, and a greater Applied Pressure Gradient lead to a faster fluid flow and, therefore, a short residence time. We show that if κa ≤ 0.001 the residence time distribution can be approximated by that for the case of a laminar flow, and if κa ≥ 500, the residence time distribution can be approximated by that for the case of ...
Harshad Sanjay Gaikwad - One of the best experts on this subject based on the ideXlab platform.
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Analysis of the Effects of Joule Heating and Viscous Dissipation on Combined Pressure-Driven and Electrokinetic Flows in a Two-Parallel Plate Channel with Unequal Constant Temperatures:
Proceedings of the Institution of Mechanical Engineers Part E: Journal of Process Mechanical Engineering, 2018Co-Authors: Harshad Sanjay Gaikwad, Pranab Kumar Mondal, Dipankar N Basu, Nares Chimres, Somchai WongwisesAbstract:In this article, we perform an entropy generation analysis for the micro channel heat sink applications where the flow of fluid is actuated by combined influences of Applied Pressure Gradient and e...
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Effect of thermal asymmetries on the entropy generation analysis of a variable viscosity Couette–Poiseuille flow
Proceedings of the Institution of Mechanical Engineers Part E: Journal of Process Mechanical Engineering, 2017Co-Authors: Pranab Kumar Mondal, Harshad Sanjay Gaikwad, Pranab Kumar Kundu, Somchai WongwisesAbstract:The influence of viscous dissipation on forced convective heat transfer and entropy generation rate in the conduction limit for a variable-viscosity flow between asymmetrically heated parallel plates is studied in an analytical framework consistent with perturbation method. The study considers a flow of Newtonian fluid under the simultaneous action of an Applied Pressure Gradient and an axial movement of the upper plate. The present study emphasizes on the effect of dissipative heat produced by the movable upper plate as well as viscous heating generated due to Applied Pressure Gradient on the underlying thermo-hydrodynamic transport. A few non-dimensional parameters such as dimensionless upper plate velocity, degree of asymmetry parameter and Brinkman number have been defined and their influential role on the variation of temperature profile, the Nusselt number and entropy generation number has been discussed in detail. The study shows that the variation of Nusselt number exhibits an unbounded swing, which, in turn, leads to appearance of the point of singularities at some cases of asymmetrical plate heating. Finally, the source of appearance of point of singularities has been discussed in view of the energy balance, and from the second-law analysis of thermodynamics.
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electroosmotic transport of immiscible binary system with a layer of non conducting fluid under interfacial slip the role Applied Pressure Gradient
Electrophoresis, 2016Co-Authors: Harshad Sanjay Gaikwad, Dipankar N Basu, Pranab Kumar MondalAbstract:We investigate the transport of immiscible binary fluid layers, constituted by one conducting (top layer fluid) and another non-conducting (bottom layer fluid) fluids in a microfluidic channel under the combined influences of an Applied Pressure Gradient and imposed electric field. We solve the transport equation governing the flow dynamics analytically and obtain the closed-form expressions of the velocity fields. We bring out the alteration in the flow dynamics, mainly attributable to the non-linear interaction between interfacial slip and the electrical double layer effect over small scales as modulated by the Applied Pressure Gradient. In particular, we show the augmentation in the net volume transport rate through the channel, emerging from an intricate competition among electrical forcing, Applied Pressure Gradient and the viscous resistance as modulated by the interfacial slip. We believe that the results of this study may be of immense consequence for the design of various microfluidic devises, which are often used for the manipulation of two immiscible fluids in different biomedical/biochemical processes.
Tatiana V. Nizkaya - One of the best experts on this subject based on the ideXlab platform.
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Principles of transverse flow fractionation of microparticles in superhydrophobic channels.
Lab on a chip, 2015Co-Authors: Evgeny S. Asmolov, Alexander L. Dubov, Tatiana V. Nizkaya, Alexander J. C. Kuehne, Olga I. VinogradovaAbstract:We propose a concept of fractionation of micron-sized particles in a microfluidic device with a bottom wall decorated by superhydrophobic stripes. The stripes are oriented at an angle α to the direction of a driving force, G, which generally includes an Applied Pressure Gradient and gravity. Separation relies on the initial sedimentation of particles under gravity in the main forward flow, and their subsequent lateral deflection near a superhydrophobic wall due to generation of a secondary flow transverse to G. We provide some theoretical arguments allowing us to quantify the transverse displacement of particles in the microfluidic channel, and confirm the validity of theoretical predictions in test experiments with monodisperse fractions of microparticles. Our results can guide the design of superhydrophobic microfluidic devices for efficient sorting of microparticles with a relatively small difference in size and density.
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Flows and mixing in channels with misaligned superhydrophobic walls.
Physical review. E Statistical nonlinear and soft matter physics, 2015Co-Authors: Tatiana V. Nizkaya, Evgeny S. Asmolov, Jiajia Zhou, Friederike Schmid, Olga I. VinogradovaAbstract:Aligned superhydrophobic surfaces with the same texture orientation reduce drag in the channel and generate secondary flows transverse to the direction of the Applied Pressure Gradient. Here we show that a transverse shear can be easily generated by using superhydrophobic channels with misaligned textured surfaces. We propose a general theoretical approach to quantify this transverse flow by introducing the concept of an effective shear tensor. To illustrate its use, we present approximate theoretical solutions and Dissipative Particle Dynamics simulations for striped superhydrophobic channels. Our results demonstrate that the transverse shear leads to complex flow patterns, which provide a new mechanism of a passive vertical mixing at the scale of a texture period. Depending on the value of Reynolds number two different scenarios occur. At relatively low Reynolds number the flow represents a transverse shear superimposed with two corotating vortices. For larger Reynolds number these vortices become isolated, by suppressing fluid transport in the transverse direction.