Mathematical model for ciliary-induced transport in MHD flow of Cu-H2O nanoßuids with magnetic induction

Motivated by novel developments in surface-modified, nanoscale, magnetohydrodynamic (MHD) biomedical devices, we study theoretically the ciliary induced transport by metachronal wave propagation in hydromagnetic flow of copper-water nanofluids through a parallel plate channel. Under the physiological constraints, creeping flow is taken into consideration i.e. inertial forces are small compared with viscous forces. The metachronal wavelength is also considered as very large for cilia induced MHD flow. Magnetic Reynolds number is sufficiently large to invoke magnetic induction effects. The physical problem is linearized and exact solutions are developed for the resulting boundary value problem. Closed-form expressions are presented for the stream function, pressure rise, induced magnetic field function and temperature. Mathematica symbolic software is used to compute and illustrate numerical results. The influence of physical parameters on velocity profile, pressure gradient and trapping of bolus are discussed with the aid of graphs. The present computations are applicable to simulations of flow control of in nano-magneto-biomimetic technologies

Recent Trends in Coatings and Thin Film–Modeling and Application

Over the past four decades, there has been increased attention given to the research of fluid mechanics due to its wide application in industry and phycology. Major advances in the modeling of key topics such Newtonian and non-Newtonian fluids and thin film flows have been made and finally published in the Special Issue of coatings. This is an attempt to edit the Special Issue into a book. Although this book is not a formal textbook, it will definitely be useful for university teachers, research students, industrial researchers and in overcoming the difficulties occurring in the said topic, while dealing with the nonlinear governing equations. For such types of equations, it is often more difficult to find an analytical solution or even a numerical one. This book has successfully handled this challenging job with the latest techniques. In addition, the findings of the simulation are logically realistic and meet the standard of sufficient scientific value

A numerical study of magnetohydrodynamic transport of nanofluids from a vertical stretching sheet with exponential temperature-dependent viscosity and buoyancy effects

In this paper, a mathematical study is conducted of steady incompressible flow of a temperature-dependent viscous nanofluid from a vertical stretching sheet under applied external magnetic field and gravitational body force effects. The Reynolds exponential viscosity model is deployed. Electrically-conducting nanofluids are considered which comprise a suspension of uniform dimension nanoparticles suspended in viscous base fluid. The nanofluid sheet is extended with a linear velocity in the axial direction. The Buonjiornio model is utilized which features Brownian motion and thermophoresis effects. The partial differential equations for mass, momentum, energy and species (nano-particle concentration) are formulated with magnetic body force term. Viscous and Joule dissipation effects are neglected. The emerging nonlinear, coupled, boundary value problem is solved numerically using the Runge–Kutta fourth order method along with a shooting technique. Graphical solutions for velocity, temperature, concentration field, skin friction and Nusselt number are presented. Furthermore stream function plots are also included. Validation with Nakamura’s finite difference algorithm is included. Increasing nanofluid viscosity is observed to enhance temperatures and concentrations but to reduce velocity magnitudes. Nusselt number is enhanced with both thermal and species Grashof numbers whereas it is reduced with increasing thermophoresis parameter and Schmidt number. The model is applicable in nano-material manufacturing processes involving extruding sheets

Thermal enhancement and numerical solution of blood nanofluid flow through stenotic artery

The blood flow through stenotic artery is one of the important research area in computational fluid mechanics due to its application in biomedicine. Aim of this research work is to investigate the impact of nanoparticles on the characteristics of human blood flow in a stenosed blood artery. In under consideration problem Newtonian fluid is assumed as human blood. Newtonian fluid flows through large blood vessels (more than 300 mu m). The constitutive equations together with the boundary conditions are diminished to non-dimensional form by using boundary layer approximation and similarity transfiguration to attain the solution of velocity and temperature distribution of blood flow through arterial stenosis numerically with the help of Matlab bvp4c. The results for physical quantities at cylindrical surface are calculated and their effects are also presented through tables. The heat transfer rate increases throughout the stenosed artery with the concentration of copper nanoparticle. Velocity curve decreases by increasing the values of flow parameter and nanoparticle volume fraction. Temperature curve increases due to increase in the values of nanoparticle volume fraction and decrease in Prandtl number.The work of U.F.-G. was supported by the government of the Basque Country for the ELKA-RTEK21/10 KK-2021/00014 and ELKARTEK22/85 research programs, respectively. Additionally, this work was supported by the Researchers Supporting Project Number (RSP-2021/33), King Saud University, Riyadh, Saudi Arabia

Cattaneo-Christov heat flux model for second grade nanofluid flow with Hall effect through entropy generation over stretchable rotating disk

The second grade nanofluid flow with Cattaneo-Christov heat flux model by a stretching disk is examined in this paper. The nanofluid flow is characterized with Hall current, Brownian motion and thermophoresis influences. Entropy optimization with nonlinear thermal radiation, Joule heating and heat absorption/generation is also presented. The convergence of an analytical approach (HAM) is shown. Variation in the nanofluid flow profiles (velocities, thermal, concentration, total entropy, Bejan number) via influential parameters and number are also presented. Radial velocity, axial velocity and total entropy are enhanced with the Weissenberg number. Axial velocity, tangential velocity and Bejan number are heightened with the Hall parameter. The total entropy profile is enhanced with the Brinkman number, diffusion parameter, magnetic parameter and temperature difference. The Bejan number profile is heightened with the diffusion parameter and temperature difference. Arithmetical values of physical quantities are illustrated in Tables

Computational modelling of micropolar blood-based magnetised hybrid nanofluid flow over a porous curved surface in the presence of artificial bacteria

This work provides a brief comparative analysis of the influence of heat creation on micropolar blood-based unsteady magnetised hybrid nanofluid flow over a curved surface. The Powell–Eyring fluid model was applied for modelling purposes, and this work accounted for the impacts of both viscous dissipation and Joule heating. By investigating the behaviours of Ag and TiO2 nanoparticles dispersed in blood, we aimed to understand the intricate phenomenon of hybridisation. A mathematical framework was created in accordance with the fundamental flow assumptions to build the model. Then, the model was made dimensionless using similarity transformations. The problem of a dimensionless system was then effectively addressed using the homotopy analysis technique. A cylindrical surface was used to calculate the flow quantities, and the outcomes were visualised using graphs and tables. Additionally, a study was conducted to evaluate skin friction and heat transfer in relation to blood flow dynamics; heat transmission was enhanced to raise the Biot number values. According to the findings of this study, increasing the values of the unstable parameters results in increase of the blood velocity profile

Heat Transfer Attributes of Gold–Silver–Blood Hybrid Nanomaterial Flow in an EMHD Peristaltic Channel with Activation Energy

The heat enhancement in hybrid nanofluid flow through the peristaltic mechanism has received great attention due to its occurrence in many engineering and biomedical systems, such as flow through canals, the cavity flow model and biomedicine. Therefore, the aim of the current study was to discuss the hybrid nanofluid flow in a symmetric peristaltic channel with diverse effects, such as electromagnetohydrodynamics (EMHD), activation energy, gyrotactic microorganisms and solar radiation. The equations governing this motion were simplified under the approximations of a low Reynolds number (LRN), a long wavelength (LWL) and Debye–Hückel linearization (DHL). The numerical solutions for the non-dimensional system of equations were tackled using the com-putational software Mathematica. The influences of diverse physical parameters on the flow and thermal characteristics were computed through pictorial interpretations. It was concluded from the results that the thermophoresis parameter and Grashof number increased the hybrid nanofluid velocity near the right wall. The nanoparticle temperature decreased with the radiation parameter and Schmidt number. The activation energy and radiation enhanced the nanoparticle volume fraction, and motile microorganisms decreased with an increase in the Peclet number and Schmidt number. The applications of the current investigation include chyme flow in the gastrointestinal tract, the control of blood flow during surgery by altering the magnetic field and novel drug delivery systems in pharmacological engineering.This work was supported by the Deanship of Scientific Research, Vice Presidency for Graduate Studies and Scientific Research, King Faisal University, Saudi Arabia (Project No. AN00052)

Energy conservation of bio-nanofluids past a needle in the presence of Stefan blowing : lie symmetry and numerical simulation

Thermal energy management associated with the transmission of heat is one of the main problems in many industrial setups (e.g. pharmaceutical, chemical and food) and bioengineering devices (e.g. hospital ventilation, heating, cooling devices, heat exchanger and drying food, etc). The current study aims to examine thermo-bioconvection of oxytactic microorganisms taking place in a nanofluid-saturated needle with the magnetic field. Stefanblowing is applied. The leading equations of continuity, momentum and energy, species transport equations for oxygen concentration and population density of microorganisms are reduced dimensionless and Lie symmetry group transformations are used to generate appropriate invariant transformations. The resulting similarity boundary value problem (in which the blowing parameter is coupled with concentration) have been simulated using MATLAB (2015a) bvp5c built in function. The impact of the emerging factors on the nondimensional velocity, temperature, nanoparticle concentration and motile microorganism density functions and their slopes at the wall, are pictured and tabulated. Justification with published results are included. It is found that all physical quantities decrease with Stefan blowing and increase with power law index parameter. With elevation in magnetic field parameter i.e., Lorentzian drag force, the friction factor reduces while the local Nusselt number, local Sherwood number, and the local motile microorganism density wall gradient increase. Present study could be used in food and pharmaceutical industries, chemical processing equipment, fuel cell technology, enhanced oil recovery, etc

Numerical solution of bio-nano-convection transport from a horizontal plate with blowing and multiple slip effects

In this paper, a new bio-nano-transport model is presented. The effects of first and second order velocity slips, thermal slip, mass slip, and gyro-tactic (torque-responsive) microorganism slip of bioconvectivenanofluid flow from amoving plate under blowing phenomenon are numerically examined. The flow model is expressed by partial differential equations which areconverted to a similar boundary value problem bysimilarity transformations. The boundary value problem is converted to a system of nonlinear equationswhich are then solved by a Matlab nonlinear equation solver fsolveintegrated with a Matlab ODEsolverode15s. The effects of selected control parameters (first order slip, second order slip, thermal slip, microorganism slip, blowing, nanofluid parameters) on the non-dimensional velocity, temperature, nanoparticle volume fraction, density ofmotile micro-organism, skin friction coefficient, heat transfer rate, mass flux of nanoparticles andmass fluxof microorganismsare analyzed. Our analysis reveals that a higher blowing parameter enhances micro-organism propulsion, flow velocityand nano-particle concentration, and increases the associated boundary layerthicknesses. A higher wall slip parameter enhances mass transfer and accelerates the flow. The MATLAB computations have been rigorously validated with the second-order accurate finite difference Nakamura tri-diagonal method.The current study is relevant to microbial fuel cell technologies which combine nanofluid transport, bioconvection phenomena and furthermore finds applications in nano-biomaterials sheetprocessing systems

Numerical study of nanofluid-based direct absorber solar collector systems with metallic/carbon nanoparticles, multiple geometries and multi-mode heat transfer

Nanofluids are complex colloidal suspensions comprising nanoparticles (metallic or carbon based or both) suspended in a base fluid (e.g. water). The resulting suspension provides demonstrably greater thermal performance than base fluids on their own without the agglomeration or sedimentation effects associated with larger (micron-sized) particles. The substantial elevation in thermal conductivity achieved with nanoparticles has made nanofluids very attractive for numerous energy applications including solar collectors. Solar energy is a clean, renewable source available and is essential for all life to exist on earth. Current technology which harvests solar energy with heat transfer fluids (HTFs) e.g., Direct Absorber Solar Collectors (DASCs), Flat Plat Solar Collector (FPCs), Parabolic Trough Solar Collector (PTSCs) etc, still requires continuous improvement in achieving higher efficiencies and greater sustainability. Nanotechnology has emerged as a significant area in recent years and features the use of sophisticated “green” nanomaterials embedded in conventional engineering materials. In this PhD a range of different DASC geometries are explored (annular, trapezoidal, prismatic, quadrilateral, biomimetic channel etc) with a variety of real nanofluids (water-based with metallic nanoparticles such as silver, copper, gold, zinc, titanium etc or carbon based e.g. diamond, graphite etc). Viscous incompressible laminar flows using Newtonian fluid models (Navier-Stokes equations) with thermal convection and radiative heat transfer are considered both with and without thermal buoyancy. Several thermal radiative flux models are deployed to mimic solar radiation effects such as the Rosseland model, P1 Traugott model, Chandrasekhar discrete ordinates model (DOM). ANSYS FLUENT and MAPLE symbolic software are used as the numerical tools to solve the relevant boundary value problems. Generally, the Tiwari-Das nanoscale model is used although the Buongiorno two-component nanofluid model (with thermophoresis and Brownian motion) has also been deployed. Extensive visualizations of streamline and isotherms are computed. Validation with alternative numerical methods and experimental studies is also included. Comprehensive appraisal of the relative performance of different nanofluids is evaluated. Generally, non-magnetic nanoparticles are studied although for the biomimetic channel (solar pump) case magnetic nanoparticles are addressed. The simulations show the significant improvement in thermal conductivities (and thermal efficiency) achieved with different types of geometry and nanoparticle type. Aspect ratio and inclination effects are also considered for some DASC cases. Extensive physical interpretation of thermofluid characteristics is provided. Where possible key dimensionless scaling parameters (Rayleigh number, Nusselt number, Prandtl number, Rosseland number etc) are utilized. The analyses reported herein constitute significant novel developments in solar collector nanofluid dynamics and many chapters have been published in leading international journals and conferences. The results have furnished good guidance for solar designers to assist in the selection of different geometries, nanoparticle types and volume fraction (percentage doping) for larger scale deployment in the future. Furthermore, some pathways for extending the current simulations to e.g. non-Newtonian nanofluid physics, turbulence etc are also outlined