MHD thermogravitational convection and thermal radiation of a micropolar nanoliquid in a porous chamber

This work studies the thermogravitational transmission and thermal radiation of micropolar nanoliquid within

Analysis of conjugate natural convection within a porous square enclosure occupied with micropolar nanofluid using local thermal non-equilibrium model

This work aims to study the conjugate natural convection of micropolar nanofluid within a porous enclosure considering local thermal non-equilibrium model. The Galerkin finite element method is employed to solve the coupled and non-linear equations. The governing parameters are Darcy–Rayleigh number Ra = 10–1000, porosity ε = 0.1–0.9, interface parameter H = 1–1000, Kr = 0.1–10, volume fraction of the nanofluid φnf = 0–0.08, vortex viscosity parameter Δ = 0–3, the width of the solid wall d = 0.1–0.4 and ratio of wall thermal conductivity to that of the base fluid Rk = 0.1–10. It has been revealed that the power of micro-rotations increases with Darcy–Rayleigh number, vortex viscosity parameter, ratio of wall thermal conduction to that of base fluid, interface parameter (Kr and H) in conditions that declines with thickness of the solid wall and porosity. The Nusselt numbers for both phases in the porous medium significantly decline as thickness of the solid wall rises, with the exception of d = 0.35. Also, it can be concluded as the porosity parameter increases for the passing flow, the nanofluid flow is governed by the classic Navier-Stokes equations

Variable magnetic forces impact on magnetizable hybrid nanofluid heat transfer through a circular cavity

This research deals with the analysis of magnetizable hybrid nanofluid of MWCNT-Fe3O4/H2O inside a circular cavity with two circular heaters. A wire carrying electrical current has been located in the center of each heater. The magnetic fields strengths created by the wires carrying electrical current are not the same. The governing parameters studied includes Rayleigh number (Ra = 104 to 106), location angle of heaters α = 0–π/2, the magnetic strengths ratio parameter γr = 0.2–5, magnetic number Mnf = 0–1000, Hartmann number Ha = 0–50, nanocomposite particles concentration φ = 0–0.3%. Results demonstrate that dispersing the hybrid nanoparticles of MWCNT-Fe3O4 inside the host fluid augments the convective heat transfer

Natural convection of magnetic hybrid nanofluid inside a double-porous medium using two-equation energy model

Porous media and nanofluids can be used for heat transfer enhancement in different industrial sectors. Very often technical systems consist of several porous layers. At the same time, hybrid nanofluids can be more effective in comparison with a nanofluid including only one kind of nanoparticles. The present study deals with a numerical analysis of MHD hybrid nanofluid natural convection heat transfer within the T-shaped cavity heated from the bottom and cooled from the upper chamber walls. Two different porous layers form the considered enclosure. The viscosity of the nanofluid depends on the magnetic field intensity. Governing equations written in dimensionless primitive variables using the extended Darcy–Brinkman–Forchheimer model for the porous medium, single-phase nanofluid model and local thermally non-equilibrium model were solved by the finite element method. Wide-range governing parameters impacts were examined to define the development of nanofluid flow and heat transfer inside the enclosure. Heat transfer enhancement can be gained for low values of the solid-liquid interface convection parameter, magnetic field viscosity parameter and high values of the thermal conductivity ratio

Magneto-Hydrodynamic Flow of Micropolar Nanofluid Containing Motile Microorganisms Passing over a Vertical Stretching Sheet with Magnetic Field Dependent Viscosity

Abstract: This study investigates the mixed convection heat transfercharacteristics of micropolar nanofluid containing motile microorganismsas it is passing over a stretching sheet. The governing equations of thefluid flow and boundary conditions are solved via similarity analysisusing the fourth-order Runge–Kutta method. To verify the accuracy andvalidity of the method, the results are compared with those of severalprevious studies. The results are presented in terms of distribution ofthe velocity, particle micro-rotation, temperature, nanoparticleconcentration, and density of motile microorganisms over the stretchingsheet. The skin friction, coupled stress, mass transfer rate, and therate of microorganism transfer away from the sheet are also examined. Itcan be concluded that the Nusselt number, coupled stress, frictioncoefficient, and Sherwood number are independent of the bioconvectionLewis number Lb. On the other hand, the rate of motilemicroorganism transfer away from the sheet to the fluid increases withLb

Fluid Flow and Heat Transfer Analysis of a Nanofluid Containing Motile Gyrotactic Micro-Organisms Passing a Nonlinear Stretching Vertical Sheet in the Presence of a Non-Uniform Magnetic Field; Numerical Approach.

The behavior of a water-based nanofluid containing motile gyrotactic micro-organisms passing an isothermal nonlinear stretching sheet in the presence of a non-uniform magnetic field is studied numerically. The governing partial differential equations including continuity, momentums, energy, concentration of the nanoparticles, and density of motile micro-organisms are converted into a system of the ordinary differential equations via a set of similarity transformations. New set of equations are discretized using the finite difference method and have been linearized by employing the Newton's linearization technique. The tri-diagonal system of algebraic equations from discretization is solved using the well-known Thomas algorithm. The numerical results for profiles of velocity, temperature, nanoparticles concentration and density of motile micro-organisms as well as the local skin friction coefficient Cfx, the local Nusselt number Nux, the local Sherwood number Shx and the local density number of the motile microorganism Nnx are expressed graphically and described in detail. This investigation shows the density number of the motile micro-organisms enhances with rise of M, Gr/Re2, Pe and Ω but it decreases with augment of Rb and n. Also, Sherwood number augments with an increase of M and Gr/Re2, while decreases with n, Rb, Nb and Nr. To show the validity of the current results, a comparison between the present results and the existing literature has been carried out

Local thermal non-equilibrium analysis of conjugate free convection within a porous enclosure occupied with Ag–MgO hybrid nanofluid

Current investigation aims to analyze the conjugate free convection inside a porous square cavity occupied with Ag–MgO hybrid nanofluid using the local thermal non-equilibrium (LTNE) model. Hybrid nanofluids are a novel kind of enhanced working fluids, engineered with enhanced thermo-physical and chemical properties. Two solid walls located between the horizontal bounds in two sides of cavity play the role of a conductive interface between the hot and cold walls, and moreover, the top and bottom bounds have been insulated. The governing differential equations are obtained by Darcy model and then for better representation of the results, converted into a dimensionless form. The finite element method is utilized to solve the governing equations. To evaluate the correctness and accuracy of the results, comparisons have been performed between the outcomes of this work and the previously published results. The results indicate that using the hybrid nanoparticles decreases the flow strength and the heat transfer rate. The heat transfer rate augments when Rk rises and the flow strength augments when Ra grows. Enhancing the porosity increases strongly the size and strength of the vortex composed inside the porous medium. When Kr is low, the heat transfer rate is low and by increasing Kr, thermal fields become closer to each other. The effect of hybrid nanoparticles on thermal fields with the thinner solid walls is more than that the thicker ones. An increment in H eventuates the enhancement of heat transfer and hence, the thermal boundary layer thickness. By increasing the volume fraction of the hybrid nanoparticles, Nuhnf and Nus decrease in constant Ra. Besides, increase in Ra enhances the Nuhnf and Nus. For a certain d, the reduction of Nus due to using the hybrid nanoparticles is more than that for Nuhnf. The increment of d lessens Nuhnf for all values of Kr and has not specific trends for Nus. Utilizing hybrid nanoparticles decreases Nus (except d = 0.4), rises Nus when Kr 18, while it can increase Nus for Kr[42. In constant d, increment of H, respectively, decreases and boosts Nuhnf and Nus. For all values of d, increment of e declines Nuhnf. In low value of d, the increase in e reduces Nus, whereas at higher values, Nus has continuously enhancing trend. For different values of d, the increase in e scrimps Nuhnf. The increment of d and also e, and H are, respectively, decreases and increases the heat transfer rate

Dressings Combined with Injection of Meglumine Antimoniate in the Treatment of Cutaneous Leishmaniasis: A Randomized Controlled Clinical Trial

Background:Cutaneous leishmaniasis (CL) is a neglected infectious disease and a major health problem in several developing countries. Despite some reasonable explanation for their potential benefits, there is only trace evidence regarding the role of dressings in the treatment of CL.Methods:This randomized, assessor-blind, controlled, clinical trial was conducted in an endemic area for CL caused by Leishmania major in Iran to assess the efficacy of administration of weekly intralesional meglumine antimoniate (i.l.MA) either alone or combined with application of a silver or a non-silver polyester dressing on their lesions for 6 weeks. After screening of 241 patients with CL lesions, 83 eligible patients with 158 lesions were randomly allocated in three arms of the study. Eligibility criteria included parasitologically confirmed CL, age of 12 to 60 years; willingness to participate, duration of lesion<3 months, number of lesions<5, largest ulcer diameter<5 cm. Pregnant or lactating women were excluded. The primary outcome was absolute risk reduction (ARR) based on the proportion of complete healing, which was defined as more than 75 reduction in the size of the lesion compared with baseline in each group at the termination of treatment and 1 month later.Findings:ARR (95 Confidence Interval CI) in i.l.MA versus i.l.MA+non-silver dressing groups was 5.98% (-7.07% to 20.25%), between i.l.MA versus i.l.MA+silver dressing groups was -0.23% (-13.53% to 14.82%), and between i.l.MA+non-silver dressing versus i.l.MA+silver dressing groups was -6.21%(-18.28% to 6.52%) after 6 weeks of treatment. ARR (95% CI) in i.l.MA versus i.l.MA+non-silver dressing groups was -2.22% (-22.12% to 18.10%), between i.l.MA versus i.l.MA+silver dressing groups was 3.64% (-15.36% to 22.82%), and between i.l.MA+non-silver dressing versus i.l.MA+silver dressing groups was 5.86% (-12.86% to 24.31%) 1 month later.Conclusion:It could not be demonstrated that the efficacy of i.l.MA was improved by either dressing. Trial Registration:Iranian Registry of Clinical Trials (IRCT.ir) IRCT138707201166N2. © 2013 Khatami et al

Effects of <i>M</i> and <i>n</i> on the nanoparticles concentration.

<p>Effects of <i>M</i> and <i>n</i> on the nanoparticles concentration.</p

Effects of <i>Ec</i> and <i>Gr/Re</i>^<i>2</i> on the dimensionless temperature.

<p>Effects of <i>Ec</i> and <i>Gr/Re</i>^<i>2</i> on the dimensionless temperature.</p