Steady Boundary Layer Flow Of Nanofluid With Microorganism

In this thesis, an analysis of two and three dimensional laminar convective boundary layer flow of a nanofluid with microorganism is investigated. It involves two and three dimensional laminar convective external boundary layer flow with heat and mass transfer under various physical configurations as well as geometries

Computation of melting dissipative magnetohydrodynamic nanofluid bioconvection with second order slip and variable thermophysical properties

This paper studies the combined effects of viscous dissipation, first and second order slip and variable transport properties on phase-change hydromagnetic bio-nanofluid convection flow from a stretching sheet. Nanoscale materials possess a much larger surface to volume ratio than bulk materials which significantly modifies their thermodynamic and thermal properties and lowers substantially the melting point. Gyrotactic non-magnetic micro-organisms are present in the nanofluid. The transport properties are assumed to be dependent on the concentration and temperature. Via appropriate similarity variables, the governing equation with boundary conditions are converted to nonlinear ordinary differential equations and are solved using the BVP4C subroutine in the symbolic software Matlab. The non-dimensional boundary value features a melting (phase change) parameter, temperature-dependent thermal conductive parameter, first as well as second order slip parameters, mass diffusivity parameter, Schmidt number, microorganism diffusivity parameter, bioconvection Schmidt number, magnetic body force parameter, Brownian motion and thermophoresis parameter. Extensive computations are visualized for the influence of these parameters. The present simulation is of relevance in the fabrication of bio-nanomaterials for bio-inspired fuel cells

Computation of bio-nano-convection power law slip flow from a needle with blowing effects in a porous medium

Transport phenomena with fluid flow, heat, mass, nanoparticle species and microorganism transferexternal to a needle in a porous medium have many biomedical engineering applications (e. g.hypodermic needles used in hemotology). It is also used to design many biomedical engineeringequipments and coating flows with bio-inspired nanomaterials. Coating flows featuringcombinations of nanoparticles and motile micro-organisms also constitute an important applicationarea. A mathematical model for convective external boundary layer flow of a power-law nanofluidcontaining gyrotactic micro-organisms past a needle immersed in a Darcy porous medium isdeveloped. Multiple slips boundary conditions and Stefan blowing effects at the needle boundaryare taken into account. The model features a reduced form of the conservation of mass, momentum,energy, nanoparticle species and motile micro-organism equations with appropriate coupledboundary conditions. The governing nonlinear partial differential equations (NPDEs) areconverted to dimensionless form and appropriate invariant transformations are applied to obtainsimilarity ordinary differential equations (SODE). The transformed equations have been solvednumerically using the in-built Matlab bvp4c function. The influence of the emerging parameterson the dimensionless velocity, temperature, nanoparticle concentration, motile micro-organismdensity functions, skin friction, heat, mass, and micro-organism transfers) are discussed in detail.It is found that velocity decreases whilst temperature, concentration, and density of motile microorganism increase with an increase in blowing parameter for shear thinning (pseudoplastic),Newtonian, and shear thickening (dilatant) fluids. It is also found that skin friction, Nusselt number(dimensionless heat transfer rate), Sherwood number (dimensionless nanoparticle mass transferrate) and motile micro-organism wall density gradient decrease with increasing blowing, Darcy,power law and needle size parameters. Comparison with the earlier published results is alsoincluded and an excellent agreement is obtained

Anisotropic slip magneto-bioconvection flow from a rotating cone to a nanofluid with Stefan Blowing effects

A mathematical model for two dimensional steady laminar natural convective anisotropic slip boundary layer flows from a rotating vertical cone embedded in ethylene glycol bionanofluid is presented. The influence of Stefan blowing is also taken into account. Four different nonparticles namely Copper (Cu), Alumina (Al2O3), Copper Oxide (Cuo), Titanium Oxide (TiO2) are explored. Suitable similarity transformations are used to convert the governing equations into non-linear ordinary differential equations. These are then solved numerically, with appropriate boundary conditions, utilizing an implicit finite difference method (the BVP5C code in MATLAB). During computation Sc, Lb, Le and Lb are presented as unity, whilst Pr is taken as 151.The effects of the governing parameters on the dimensionless velocities, temperature, nanoparticle volume fraction, density of motile microorganisms as well as on the local skin friction, local Nusselt, Sherwood number and motile micro-organism number density are thoroughly examined via tables and graphs. It is found that the skin friction factor increases with tangential slip, magnetic field and Schmidt number whilst it decreases with blowing parameter and spin parameters. It is further observed that both the friction and heat transfer rates are highest for copper nanoparticles and lowest for TiO2 nanoparticles. Validation of the BVP5C numerical solutions with published results for several special cases of the general model is included. The study is relevant to electro-conductive bio-nano-materials processing

Influence of Stefan blowing on nanofluid flow submerged in microorganisms with leading edge accretion or ablation

The unsteady forced convective boundary layer flow of viscous incompressible fluid containing both nanoparticles and gyrotactic microorganisms, from a flat surface with leading edge accretion (or ablation), is investigated theoretically. Utilizing appropriate similarity transformations for the velocity, temperature, nanoparticle volume fraction and motile microorganism density, the governing conservation equations are rendered into a system of coupled, nonlinear, similarity ordinary differential equations. These equations, subjected to imposed boundary conditions, are solved numerically using the Runge-Kutta-Fehlberg fourth-fifth order numerical method in the MAPLE symbolic software. Good agreement between our computations and previous solutions is achieved. The effect of selected parameters on flow velocity, temperature, nano-particle volume fraction (concentration) and motile microorganism density function is investigated. Furthermore, tabular solutions are included for skin friction, wall heat transfer rate, nano-particle mass transfer rate and microorganism transfer rate. Applications of the study arise in advanced micro-flow devices to assess nanoparticle toxicity

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

Steady Boundary Layer Flow Of Nanofluid With Microorganism

In this thesis, an analysis of two and three dimensional laminar convective boundary layer flow of a nanofluid with microorganism is investigated. It involves two and three dimensional laminar convective external boundary layer flow with heat and mass transfer under various physical configurations as well as geometries. The parameters that involved in this research are consist of magnetic field, heat generation/absorption, velocity slip, thermal slip, mass slip, microorganisms slip, viscosity, thermal conductive, mass diffusivity, and microorganism diffusivity. Melting heat transfer rate, Stefan blowing and multiple boundary conditions are taken into account. The fluid is characterized to be Newtonian, non- Newtonian, viscous, incompressible, magnetohydrodynamic and has constant or variable physical properties. Steady boundary layers are considered and appropriate transformations are used to transform the partial differential equations into nonlinear ordinary differential equations. The transformed equations are solved numerically using the bvp4c in Matlab for various values of the controlling parameters. Graphs are plotted to display the effect of the controlling parameters on the dimensionless velocity, viscosity, temperature, concentration (nanoparticle volume fraction), microorganism as well as skin friction factor, rate of heat, rate of mass transfer and rate of motile microorganism. The numerical solution for the skin friction factor, rate of heat, rate of mass transfer and rate of motile microorganism are generated for various values of the parameters. The flow field and other quantities of physical interest are found to be significantly influenced by the controlling parameters. A comparison with previously published work is carried out and the results are found to be in a good agreement

Three dimensional stagnation point flow of bionanofluid with variable transport properties

Bionanofluid is a nanofluid in which bioconvection occurs. This paper studies the three dimensional steady stagnation point flow of a bionanofluid with variable transport properties. All the transport properties are dependent on the concentration. Zero mass flux and thermal convective boundary conditions are taken into account. The governing equations of the problem are nondimensionalized and transformed into a set of similarity equations using similarity transformation generated by Lie group analysis. The transformed equations are solved numerically using the Runge-Kutta-Fehlberg fourth-fifth order numerical method (RKF45). The solutions depend on the viscosity parameter, thermal conductive parameter, mass diffusivity parameter, microorganism diffusivity parameter, Schmidt number, bioconvection Schmidt number and Péclet number. These controlling parameters affect the dimensionless velocity, temperature, nanoparticle volume fraction, microorganisms, the skin friction coefficient, the local Nusselt number and the Sherwood number as well as the motile microorganism rate and are displayed graphically. The results were found to be in good agreement with previous related studies