Analytical And Numerical Study Of Boundary Layer Flow Of Newtonian And Non-Newtonian Fluids With Heat And Mass Transfer

Boundary Layer phenomenon is technically a region where the fluid is affected due to the motion of solid body.Due to that fact,viscous forces are more dominant in the boundary layer region.These regions are usually determined in the infinite or semi-infinite complex nature domain that is based upon Navier-Stokes equations.Al-though,solution of Navier-Stokes equations is not developed in the literature so far but in present thesis the solution of both Newtonian and non-Newtonian fluid models for semi-infinite domain by using similarity transformation is determined.As we know that heat transfer is fundamental requirement where we need to re-move,add or transfer heat from one place to another.All these factors depending upon the thermal conductivity of the working/base fluid.Most of the liquids/fluids that are used in the industry level have very poor thermal conductivity.To overcome this poor thermal conductivity of working fluid,nanoparticles are introduced to enhance the thermal conductivity of working fluids.By introducing the nanoparticles,concentra-tion of the fluid might be affected in the boundary layer region therefore it is necessary to encounter the concentration equation as well.So in the present thesis energy and concentration equation are considered into the loop after coupling with momentum e-quation.Throughout in this thesis,mathematical models consist of highly nonlinear sys-tem of coupled differential equations with semi-infinite domain.Since these differen-tial equations are highly nonlinear so their closed form solution is not possible.So,the present thesis determines the approximate solutions by using numerical method(via Finite Difference Method)and semi-analytical method(via Homotopy Analysis Method).The thesis is divided into various chapters whose description is given below:Chapter one gives the detailed literature review related to the present work.The derivation of basic equations which governs the flow,heat and mass transfer is also derived in frame of cartisian coordinates.Detailed numerical and analytical procedure via Finite Difference Method and Homotopy Analysis Method,respectively,are pre-sented via simple illustrative examples.Chapter two is devoted to the study non-Newtonian fluid flow over horizontal linearly stretching sheet.The non-Newtonian Prandtl fluid model has been utilized.Furthermore,nanofluid is considered as working fluid and Buongiorno's fluid model has been used to study the nanofluid characteristics.Passive control of nanoparticles has been considered by incorporating zero normal flux at the boundary.The govern-ing equations are solved using Finite Difference Method.Effects of various physical parameter,including,non-Newtonian Prandtl fluid parameter,Brownian motion pa-rameter,and thermophoresis parameter on the nanofluid flow velocity,temperature,concentration distribution,wall skin friction and heat transfer rate has been analyzed.The results have been published in the "Chinese Journal of Physics,55(2017)1561-1568".Chapter three gives the study of non-Newtonian Prandtl nanofluid flow over ver-*tical stretching surface.Such problem includes the buoyancy assisting and opposing flow effects.Buongiorno's fluid model has been utilized to study the Brownian and thermophoresis effects.The solution of the governing equations is obtained numeri-cally via Finite Difference Method.The effects of the emerging physical parameters including buoyancy assisting and opposing parameter on the flow,heat and mass trans-fer characteristics,that are,velocity,temperature and concentration distribution,skin friction,heat and mass transfer rate,are explained in details using numerical values and graphs.Chapter four gives the study over the non-Newtonian fluid flow of Prandtl nanoflu-id over horizontal stretching sheet with homogeneous-heterogeneous chemical reac-tions.The physical problem is modeled into the mathematical model in the form of coupled nonlinear partial differential equations including the homogeneous-heteroge-nous equations.The solution of such equations is obtained using Finite Difference Method after converting it to the non-dimensional equations using similarity transfor-mation procedure.Very interesting results are discussed against the range of emerging physical parameters on flow,heat and mass transfer characteristics.Chapter five gives the study on the Newtonian nanofluid flow containing single and multi wall carbon nanotubes with water as base fluid.The flow is considered over inclined stretching surface.Moreover,entropy generation analysis is also per-formed.The governing equations are first transformed into the non-dimensional non-linear ordinary differential equations before being solved numerically via Finite Differ-ence Method.The detailed analysis on the nanofluid characteristics including entropy generation analysis is carried out and the results are discussed in details.The results have been published in the "European Physical Journal Plus,132(2017)412".Chapter six is devoted to the study the effects of thermal radiation and heat gener-ation on the flow and heat transfer of Newtonian stagnation-point flow over stretching surface.The sheet is considered subject to convective boundary.The nanofluid flow is examined using Buongiorno's nanofluid model.The effects of various emerging phys-ical parameters including Brownian motion and thermophoresis on the fluid velocity,temperature,concentration,skin friction,heat,and mass transfer are discussed in de-tails.The results have been published in the "Results in Physics,8(2018)404-414".Chapter seven is devoted to the study of the non-Newtonian nanofluid flow,heat and mass transfer using Maxwell fluid model.The solution of the governing equa-tions is obtained analytically in the form of series solution using Homotopy Analysis Method before being transformed into the suitable non-linear ordinary differential e-quation form using similarity transformation of variable technique.The effects of the physical parameters including non-Newtonian Maxwell parameter on the fluid veloci-ty,temperature,concentration,skin friction coefficient,heat and mass transfer rate are discussed in details.Chapter eight outlines the precise conclusions of the work that has been carried out throughout in this thesis.