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E Bautista - One of the best experts on this subject based on the ideXlab platform.
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pulsatile electroosmotic flow of a maxwell fluid in a Parallel Flat Plate microchannel with asymmetric zeta potentials
Applied Mathematics and Mechanics-english Edition, 2018Co-Authors: E Bautista, O Bautista, M PeraltaAbstract:The pulsatile electroosmotic flow (PEOF) of a Maxwell fluid in a Parallel Flat Plate microchannel with asymmetric wall zeta potentials is theoretically analyzed. By combining the linear Maxwell viscoelastic model, the Cauchy equation, and the electric field solution obtained from the linearized Poisson-Boltzmann equation, a hyperbolic partial differential equation is obtained to derive the flow field. The PEOF is controlled by the angular Reynolds number, the ratio of the zeta potentials of the microchannel walls, the electrokinetic parameter, and the elasticity number. The main results obtained from this analysis show strong oscillations in the velocity profiles when the values of the elasticity number and the angular Reynolds number increase due to the competition among the elastic, viscous, inertial, and electric forces in the flow.
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dispersion coefficient in an electro osmotic flow of a viscoelastic fluid through a microchannel with a slowly varying wall zeta potential
Journal of Fluid Mechanics, 2018Co-Authors: J Arcos, F Mendez, E Bautista, O BautistaAbstract:The dispersion coefficient of a passive solute in a steady-state pure electro-osmotic flow (EOF) of a viscoelastic liquid, whose rheological behaviour follows the simplified Phan-Thien–Tanner (sPTT) model, along a Parallel Flat Plate microchannel, is studied. The walls of the microchannel are assumed to have modulated and low potentials, which vary slowly in the axial direction in a sinusoidal manner. The flow field required to obtain the dispersion coefficient was solved using the lubrication approximation theory (LAT). The solution of the electric potential is based on the Debye–Huckel approximation for a symmetric electrolyte. The viscoelasticity of the fluid is observed to notably amplify the axial distribution of the effective dispersion coefficients due to the variation in the potentials of the walls. The problem was formulated for two cases: when the Debye layer thickness (EDL) was on the order of unity (thick EDL) and in the limit where the thickness of the EDL was very small compared with the height of the microchannel (thin EDL limit). Due to the coupling between the nonlinear governing equations and the sPTT fluid model, they were replaced by their approximate linearized forms and solved in the limit of using the regular perturbation technique. Here is the amplitude of the sinusoidal function of the potentials. Additionally, the numerical solution of the simplified governing equations was also obtained for and compared with the approximate solution, showing excellent agreement for . Note that the dispersion coefficient primarily depends on the Deborah number, on the ratio of the half-height of the microchannel to the Debye length, and on the assumed variation in the potentials of the walls.
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theoretical conjugate heat transfer analysis in a Parallel Flat Plate microchannel under electro osmotic and pressure forces with a phan thien tanner fluid
International Journal of Thermal Sciences, 2011Co-Authors: Juan P Escandon, F Mendez, O Bautista, E BautistaAbstract:Abstract In this paper we solve, numerically and asymptotically, the steady-state analysis of a conjugate heat transfer process in an electro-osmotic and fully developed laminar flow including Joule heating effects. In addition, the viscoelastic fluid obeys the simplified Phan-Thien-Tanner (SPTT) constitutive equation. Taking into account the finite thermal conductivity of the micro-channel wall, the dimensionless temperature profiles in the fluid and solid wall have been obtained as functions of the dimensionless parameters involved in the analysis: a conjugate parameter, α, which represents the competition between the longitudinal conductive heat in the micro-channel wall to the convective heat transfer in the fluid; e De κ 2 , a parameter that describes the viscoelastic behavior of the fluid; the well-known Peclet number, Pe; a normalized power generation term, Λ, being the ratio of heat flux from the external wall to the Joule heating (and smaller or equal to unity); the ratio of pressure to the electro-osmotic forces, Γ; and the aspect ratios of the micro-channel and the solid wall, β and ɛ, respectively. The results for the temperature fields, in the fluid and micro-channel wall show a strong dependence of the above dimensionless parameters, therefore, this set of parameters controls directly the thermal performance of this micro-channel model.
O Bautista - One of the best experts on this subject based on the ideXlab platform.
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pulsatile electroosmotic flow of a maxwell fluid in a Parallel Flat Plate microchannel with asymmetric zeta potentials
Applied Mathematics and Mechanics-english Edition, 2018Co-Authors: E Bautista, O Bautista, M PeraltaAbstract:The pulsatile electroosmotic flow (PEOF) of a Maxwell fluid in a Parallel Flat Plate microchannel with asymmetric wall zeta potentials is theoretically analyzed. By combining the linear Maxwell viscoelastic model, the Cauchy equation, and the electric field solution obtained from the linearized Poisson-Boltzmann equation, a hyperbolic partial differential equation is obtained to derive the flow field. The PEOF is controlled by the angular Reynolds number, the ratio of the zeta potentials of the microchannel walls, the electrokinetic parameter, and the elasticity number. The main results obtained from this analysis show strong oscillations in the velocity profiles when the values of the elasticity number and the angular Reynolds number increase due to the competition among the elastic, viscous, inertial, and electric forces in the flow.
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dispersion coefficient in an electro osmotic flow of a viscoelastic fluid through a microchannel with a slowly varying wall zeta potential
Journal of Fluid Mechanics, 2018Co-Authors: J Arcos, F Mendez, E Bautista, O BautistaAbstract:The dispersion coefficient of a passive solute in a steady-state pure electro-osmotic flow (EOF) of a viscoelastic liquid, whose rheological behaviour follows the simplified Phan-Thien–Tanner (sPTT) model, along a Parallel Flat Plate microchannel, is studied. The walls of the microchannel are assumed to have modulated and low potentials, which vary slowly in the axial direction in a sinusoidal manner. The flow field required to obtain the dispersion coefficient was solved using the lubrication approximation theory (LAT). The solution of the electric potential is based on the Debye–Huckel approximation for a symmetric electrolyte. The viscoelasticity of the fluid is observed to notably amplify the axial distribution of the effective dispersion coefficients due to the variation in the potentials of the walls. The problem was formulated for two cases: when the Debye layer thickness (EDL) was on the order of unity (thick EDL) and in the limit where the thickness of the EDL was very small compared with the height of the microchannel (thin EDL limit). Due to the coupling between the nonlinear governing equations and the sPTT fluid model, they were replaced by their approximate linearized forms and solved in the limit of using the regular perturbation technique. Here is the amplitude of the sinusoidal function of the potentials. Additionally, the numerical solution of the simplified governing equations was also obtained for and compared with the approximate solution, showing excellent agreement for . Note that the dispersion coefficient primarily depends on the Deborah number, on the ratio of the half-height of the microchannel to the Debye length, and on the assumed variation in the potentials of the walls.
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theoretical conjugate heat transfer analysis in a Parallel Flat Plate microchannel under electro osmotic and pressure forces with a phan thien tanner fluid
International Journal of Thermal Sciences, 2011Co-Authors: Juan P Escandon, F Mendez, O Bautista, E BautistaAbstract:Abstract In this paper we solve, numerically and asymptotically, the steady-state analysis of a conjugate heat transfer process in an electro-osmotic and fully developed laminar flow including Joule heating effects. In addition, the viscoelastic fluid obeys the simplified Phan-Thien-Tanner (SPTT) constitutive equation. Taking into account the finite thermal conductivity of the micro-channel wall, the dimensionless temperature profiles in the fluid and solid wall have been obtained as functions of the dimensionless parameters involved in the analysis: a conjugate parameter, α, which represents the competition between the longitudinal conductive heat in the micro-channel wall to the convective heat transfer in the fluid; e De κ 2 , a parameter that describes the viscoelastic behavior of the fluid; the well-known Peclet number, Pe; a normalized power generation term, Λ, being the ratio of heat flux from the external wall to the Joule heating (and smaller or equal to unity); the ratio of pressure to the electro-osmotic forces, Γ; and the aspect ratios of the micro-channel and the solid wall, β and ɛ, respectively. The results for the temperature fields, in the fluid and micro-channel wall show a strong dependence of the above dimensionless parameters, therefore, this set of parameters controls directly the thermal performance of this micro-channel model.
F Mendez - One of the best experts on this subject based on the ideXlab platform.
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dispersion coefficient in an electro osmotic flow of a viscoelastic fluid through a microchannel with a slowly varying wall zeta potential
Journal of Fluid Mechanics, 2018Co-Authors: J Arcos, F Mendez, E Bautista, O BautistaAbstract:The dispersion coefficient of a passive solute in a steady-state pure electro-osmotic flow (EOF) of a viscoelastic liquid, whose rheological behaviour follows the simplified Phan-Thien–Tanner (sPTT) model, along a Parallel Flat Plate microchannel, is studied. The walls of the microchannel are assumed to have modulated and low potentials, which vary slowly in the axial direction in a sinusoidal manner. The flow field required to obtain the dispersion coefficient was solved using the lubrication approximation theory (LAT). The solution of the electric potential is based on the Debye–Huckel approximation for a symmetric electrolyte. The viscoelasticity of the fluid is observed to notably amplify the axial distribution of the effective dispersion coefficients due to the variation in the potentials of the walls. The problem was formulated for two cases: when the Debye layer thickness (EDL) was on the order of unity (thick EDL) and in the limit where the thickness of the EDL was very small compared with the height of the microchannel (thin EDL limit). Due to the coupling between the nonlinear governing equations and the sPTT fluid model, they were replaced by their approximate linearized forms and solved in the limit of using the regular perturbation technique. Here is the amplitude of the sinusoidal function of the potentials. Additionally, the numerical solution of the simplified governing equations was also obtained for and compared with the approximate solution, showing excellent agreement for . Note that the dispersion coefficient primarily depends on the Deborah number, on the ratio of the half-height of the microchannel to the Debye length, and on the assumed variation in the potentials of the walls.
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theoretical conjugate heat transfer analysis in a Parallel Flat Plate microchannel under electro osmotic and pressure forces with a phan thien tanner fluid
International Journal of Thermal Sciences, 2011Co-Authors: Juan P Escandon, F Mendez, O Bautista, E BautistaAbstract:Abstract In this paper we solve, numerically and asymptotically, the steady-state analysis of a conjugate heat transfer process in an electro-osmotic and fully developed laminar flow including Joule heating effects. In addition, the viscoelastic fluid obeys the simplified Phan-Thien-Tanner (SPTT) constitutive equation. Taking into account the finite thermal conductivity of the micro-channel wall, the dimensionless temperature profiles in the fluid and solid wall have been obtained as functions of the dimensionless parameters involved in the analysis: a conjugate parameter, α, which represents the competition between the longitudinal conductive heat in the micro-channel wall to the convective heat transfer in the fluid; e De κ 2 , a parameter that describes the viscoelastic behavior of the fluid; the well-known Peclet number, Pe; a normalized power generation term, Λ, being the ratio of heat flux from the external wall to the Joule heating (and smaller or equal to unity); the ratio of pressure to the electro-osmotic forces, Γ; and the aspect ratios of the micro-channel and the solid wall, β and ɛ, respectively. The results for the temperature fields, in the fluid and micro-channel wall show a strong dependence of the above dimensionless parameters, therefore, this set of parameters controls directly the thermal performance of this micro-channel model.
F C Walsh - One of the best experts on this subject based on the ideXlab platform.
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a comparison of the electrochemical recovery of palladium using a Parallel Flat Plate flow by reactor and a rotating cylinder electrode reactor
Electrochimica Acta, 2011Co-Authors: J E Terrazasrodriguez, Silvia Gutierrezgranados, M A Alatorreordaz, Ponce C De Leon, F C WalshAbstract:The production of catalytic converters generates large amounts of waste water containing Pd2+, Rh3+ and Nd3+ ions. The electrochemical treatment of these solutions offers an economic and effective alternative to recover the precious metals in comparison with other traditional metal recovery technologies. The separation of palladium from this mixture of metal ions by catalytic deposition was carried out using a rotating cylinder electrode reactor (RCER) and a Parallel Plate reactor (FM01-LC) with the same cathode area (64 cm2) and electrolyte volume (300 cm3). The study was carried out at mean linear flow velocities of 1.27 < v < 11.36 cm s?1 (120 < Re = vde/v < 1080) for the FM01-LC reactor and 20 < v < 140 cm s?1 (7390 < Re = vd/v < 51,700) for the RCER. The morphology of the palladium deposits at the entrance and at the exit of the electrolyte compartment of the FM01-LC reactor showed the effect of the manifold distributors during the electrolysis; the manifolds generate micro turbulences, increasing the mass transport coefficient in these areas and favouring rapid recovery of palladium ions. More uniform high purity palladium deposits were obtained on the surface of the RCER. The cumulative current efficiency to recover 99% of Pd2+ ions in the Parallel Plate electrode reactor was 35% while the recovery of 97% of Pd2+ in the RCER was 62%. The volumetric energy consumption during the electrolysis was 0.56 kW h m?3 and 2.1 kW h m?3 for the RCER and the FM01-LC reactors, respectively. Using a three-dimensional stainless steel electrode in the FM01-LC laboratory reactor, 99% of palladium ions were recovered after 30 min of electrolysis while in the RCER, 120 min were necessary.
Juan P Escandon - One of the best experts on this subject based on the ideXlab platform.
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theoretical conjugate heat transfer analysis in a Parallel Flat Plate microchannel under electro osmotic and pressure forces with a phan thien tanner fluid
International Journal of Thermal Sciences, 2011Co-Authors: Juan P Escandon, F Mendez, O Bautista, E BautistaAbstract:Abstract In this paper we solve, numerically and asymptotically, the steady-state analysis of a conjugate heat transfer process in an electro-osmotic and fully developed laminar flow including Joule heating effects. In addition, the viscoelastic fluid obeys the simplified Phan-Thien-Tanner (SPTT) constitutive equation. Taking into account the finite thermal conductivity of the micro-channel wall, the dimensionless temperature profiles in the fluid and solid wall have been obtained as functions of the dimensionless parameters involved in the analysis: a conjugate parameter, α, which represents the competition between the longitudinal conductive heat in the micro-channel wall to the convective heat transfer in the fluid; e De κ 2 , a parameter that describes the viscoelastic behavior of the fluid; the well-known Peclet number, Pe; a normalized power generation term, Λ, being the ratio of heat flux from the external wall to the Joule heating (and smaller or equal to unity); the ratio of pressure to the electro-osmotic forces, Γ; and the aspect ratios of the micro-channel and the solid wall, β and ɛ, respectively. The results for the temperature fields, in the fluid and micro-channel wall show a strong dependence of the above dimensionless parameters, therefore, this set of parameters controls directly the thermal performance of this micro-channel model.
