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This article deals with the numerical simulation of the electroosmotic flow of methanol-based aluminum oxide (Al2O3–CH3OH) nanofluid in a tapered microchannel. The shear-thickening attributes of methanol are characterized by the Sisko fluid model. The tapered microchannel walls move with peristaltic wave velocity. Buongiorno model in combination with the Corcione model for thermal conductivity and viscosity is employed to predict the heat transfer characteristics of Al2O3–methanol nanofluid. The Maxwell–Garnett model is employed to compute the effective electric conductivity of nanofluids. The effect of the porous medium in the flow field is signified by modified Darcy's law. The salient attributes of viscous dissipation and Joule heating caused by electroosmosis are also taken into account. The approximations of the lubrication approach and the Debye–Hückel linearization are invoked in mathematical formulation for considerable simplification of the flow problem. The solutions of the acquired set of nonlinear governing equations are computed numerically through Maple 17. The graphical results for various physical quantities are also presented for physical interpretation and discussion. It is revealed that fluid becomes more viscous for enhancement in the consistency parameter. Furthermore, maintaining a larger temperature difference within microchannel produces a reduction in the concentration of nanoparticles. Temperature and velocity profiles are strongly dependent on the electroosmosis mechanism. The simulated results will be very important for designing biomicrofluidics devices dealing with rheologically complex fluids such as lubricating greases, blood, saliva or mucus. [ABSTRACT FROM AUTHOR]

Magnetohydrodynamics plays important role to manipulate the physiological fluids due to magnetic nature of physiological fluids. Magnetohydrodynamics pumps are a robust technology which provide more elegant and sustainable performance compared with conventional medical pumps. To study the effects of suspension of the nanoparticles (drugs) in physiological fluids (blood) flow are important in biomedical science and engineering. Motivated by such applications, an analytical approach is presented to study the nanoparticle shape effects on peristaltic transport of nanofluids in presence of magnetohydrodynamics in the present article. A two dimensional continuity, momentum and energy equations are considered to govern the present biophysical model. The governing equations are also linearized using lubrication theory where we consider the low Reynolds number and long wavelength approximations. Closed form solutions are obtained for axial velocity, axial pressure gradient, temperature, pressure rise, wall shear stress and stream function. The effects of three different type of shapes (bricks, cylinders, and platelets) of nanoparticles on peristaltic pumping characteristics and thermal characteristics are computed with the help of graphical illustrations. The interesting outcomes of this study are relevant to more realistic designs for ocular peristaltic pumps in drug delivery systems. [ABSTRACT FROM AUTHOR]

Peristaltic micro-pumps offer an excellent mechanism for delivery of a variety of medicines including drugs, corneal solutions etc. The surge in deployment of nanoparticles in medicine has provided new potential for such pumps. In light of this we investigate the time-dependent peristaltic flow of nanofluids with diffusive effects through a finite non-uniform channel, this geometry being more representative of real micro-pumps. Creeping flow is taken into account (inertial forces are small compared with viscous forces) i.e., Reynolds number is low (Re <1) and wavelength is also taken to be very large. The Buongiorno formulation for nanofluids is employed with an Oberbeck-Boussinesq approximation. Closed-form solutions are developed for the non-dimensional governing equations subject to physically realistic boundary conditions. Mathematica symbolic software is employed to evaluate the evolution of nanoparticle fraction, temperature, axial velocity, transverse velocity and pressure difference distribution along the length of the pump channel with variation in thermal Grashof number, basic-density (species i.e., mass) Grashof number, Brownian motion parameter and thermophoresis parameter. [ABSTRACT FROM AUTHOR]

The present study analyzes the heat energy transfer in nano flu-ids flow through the porous stretching surface. Cattanneo-Christov heat flux model is employed to study the heat energy transfer. Darcy law is used to discuss the flow characteristics over the different types of permeable sheets with suction and injection. Nanofluids is considered as water based single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) nanofluids. A comparative study for SWCNT and MWCNT is also made. Governing equations are transformed into set of ordinary differential equations using similarity transformations. The computational results are obtained by using Runge-Kutta fourth order method along with shooting technique. Numerical and graphical results are presented to discuss the effects of various physical parameters on velocity profile, temperature profile, Nusselt number, Sherwood number and skin friction coeficient for different type of nanoparticles for suction and injection cases. Stream lines and isotherms are also plotted for three different cases viz. permeable sheet with suction, impermeable sheet and permeable sheet with injection. A comparative analysis with existing results is tabulated which validate that the numerical results of present study have good correlation with existing results. The outcomes of the results show that skin friction coeficient is more for SWCNT in caparison of MWCNT and the boundary layer thickness is maximum for permeable stretching sheet with suction parameter. [ABSTRACT FROM AUTHOR]

Slip flow of a Carreau nanofluid over a stretching sheet has been investigated. Thermophoresis and Brownian motion effects are taken into account. The Navier slip, thermal, and mass convective boundary conditions are taken into account. The prevailing partial differential equations are presented and transformed into a set of nonlinear ordinary differentials using scaling transformation. Effects of the physical parameters on velocity, temperature, and concentration profiles are computed numerically using the fourth-order Runge-Kutta-Fehlberg scheme. Numerical values of local Nusselt and Sherwood numbers are calculated and discussed. The obtained results revealed that enhancing the slip parameter consequently drops the temperature and concentration profiles. Heat and mass flux at the surface decreases with increasing thermophoresis parameter. Heat transfer rate enhances while the mass transfer rate decreases with the thermal Biot number. [ABSTRACT FROM AUTHOR]

The transportation of biological and industrial nanofluids by natural propulsion like cilia movement and self-generated contraction-relaxation of flexible walls has significant applications in numerous emerging technologies. Inspired by multi-disciplinary progress and innovation in this direction, a thermo-fluid mechanical model is proposed to study the entropy generation and convective heat transfer of nanofluids fabricated by the dispersion of single-wall carbon nanotubes (SWCNT) nanoparticles in water as the base fluid. The regime studied comprises heat transfer and steady, viscous, incompressible flow, induced by metachronal wave propulsion due to beating cilia, through a cylindrical tube containing a sparse (i.e., high permeability) homogenous porous medium. The flow is of the creeping type and is restricted under the low Reynolds number and long wavelength approximations. Slip effects at the wall are incorporated and the generalized Darcy drag-force model is utilized to mimic porous media effects. Cilia boundary conditions for velocity components are employed to determine analytical solutions to the resulting non-dimensionalized boundary value problem. The influence of pertinent physical parameters on temperature, axial velocity, pressure rise and pressure gradient, entropy generation function, Bejan number and stream-line distributions are computed numerically. A comparative study between SWCNT-nanofluids and pure water is also computed. The computations demonstrate that axial flow is accelerated with increasing slip parameter and Darcy number and is greater for SWCNT-nanofluids than for pure water. Furthermore the size of the bolus for SWCNT-nanofluids is larger than that of the pure water. The study is applicable in designing and fabricating nanoscale and microfluidics devices, artificial cilia and biomimetic micro-pumps. [ABSTRACT FROM AUTHOR]

We Consider the physical model of two-dimensional hybrid nanofluids flow, which is time dependent, laminar, incompressible inside the two co-axial stretchable disks. The length of upper and lower disks is 2 s (t). The two axial and radial velocity components (u , w) depends upper the radial of disks r and normal of direction z. There exists temperature T 1 > T 2 which is constant for upper and lower disks. The continuity, momentum and energy equations are modeled in cylindrical coordinates system. The finite element technique is used to evaluate numerical solutions. It is observed that the velocity near upper and lower disks decreases by increasing the values of magnetic parameter. Increased the values of shape factor N s of (Nanoparticles) then the thermal conductivity (HDnf) decreased. The shear stress and heat transfer rate decreased by influence α , ϕ 1 , ϕ 2 but an opposite reaction observed when increase the values of M , Re and N s . [ABSTRACT FROM AUTHOR]