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Effect of electric field on dispersion of a solute in an MHD flow through a vertical channel with and without chemical reaction

Umavathi J. C., Kumar J. P., Gorla R. S. R., Gireesha B. J.

International Journal of Applied Mechanics and Engineering

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2016

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Vol. 21, no. 3

683--711

EN

The longitudinal dispersion of a solute between two parallel plates filled with two immiscible electrically conducting fluids is analyzed using Taylor’s model. The fluids in both the regions are incompressible and the transport properties are assumed to be constant. The channel walls are assumed to be electrically insulating. Separate solutions are matched at the interface using suitable matching conditions. The flow is accompanied by an irreversible first-order chemical reaction. The effects of the viscosity ratio, pressure gradient and Hartman number on the effective Taylor dispersion coefficient and volumetric flow rate for an open and short circuit are drawn in the absence and in the presence of chemical reactions. As the Hartman number increases the effective Taylor diffusion coefficient decreases for both open and short circuits. When the magnetic field remains constant, the numerical results show that for homogeneous and heterogeneous reactions, the effective Taylor diffusion coefficient decreases with an increase in the reaction rate constant for both open and short circuits.

2

Two-dimensional Model of Fluid Flow and Distribution of Nutrient Concentration in a Microfluidic Device

Wroniszewski P.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2011

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Vol. 15, No 2

135-155

EN

During the past few years, the process of miniaturisation in the field of biochemical laboratory equipment led to the introduction of the so-called "lab-on-a-chip" microdevices, which combine separate functional units into a complex, multifunctional apparatus. Fluid dynamics plays an essential role in the development of such equipment, since frequently the major part of chemical analysis is based on soluble analytes. In this work, we consider a device for the analysis of cell growth under different conditions. In this device, dozens of cell spots absorb the nutrient (analyte) from the liquid medium. The concentration of the analyte must be strictly controlled to maintain a specific microenvironment. A two-dimensional model for the flow field and the distribution of concentration of the analyte is developed taking into account the geometrical shape of the spot with a simplified absorption model. The dependence of the results on the controlling parameters is investigated in order to determine the influence of the presence of the cell spot on the distribution of the analyte.

3

Use of Taylor dispersion of a solute for immiscible viscous fluids between two plates

Kumar J. P., Umavathi J. C., Basavaraj A.

International Journal of Applied Mechanics and Engineering

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2011

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Vol. 16, no 2

399-410

EN

The Taylor dispersion of a solute is studied for two immiscible viscous fluids flowing between parallel plates. The fluids in both the regions are incompressible and the transport properties are assumed to be constant. The walls of the channel are considered to be isothermal. The closed-form solutions are obtained in both fluids' regions of the channel. The results are presented graphically for various values of pressure gradients, height of the channel, viscosity and diffusivity. The validity of the results obtained from an analytical method for two fluid model is verified by comparison with the available one fluid model results, and good agreement is found.