Flows of Nanofluids in Rotating Frame

Abstract

Low thermal efficiency of working fluids is a main problem for several heat transport mechanisms in the engineering applications. Thus several researchers are engaged to develop an innovative way for improvement of thermal efficiency of working fluids. Many researchers have suggested different mechanisms to enhance the thermal efficiency of working fluids. Out of these, the insertion of nanoparticles in the working fluid known as nanomaterial is quite attractive. In addition the nanoliquid has vital role for cooling rate requirements with high thermal efficiency. Presently nanofluid dynamics has received remarkable attention of researchers due to its thermal transport in several areas. Nanofluids have applications in engine cooling, transformer cooling, microwave tubes, impingement jets, high-power lasers, renewable energies, lubrication, cooling of welding, thermal storage and solar water heating, heat exchangers, automotive, heating and tempering process, nuclear reactors, combustion and medicine and electronic chips cooling etc. High efficient oils and lubricants can be developed by the use of nanofluid. Magnetonanofluid dynamics is an attractive field of research in which physics of electrically conducting liquids like plasma and electrolytes or salt water and liquid metals has been analyzed. Mixture of working liquid and magnetic nanoparticles is termed as magnetonanofluid. Magnetonanofluids execute intrinsic role in MHD pumps and accelerators, some arterial diseases and hyperthermia, cancer tumor treatment, reduction of blood during surgeries and sink float separation etc. Heat transfer in rotating flows is interesting area of research. It is because of their enormous applications in manufacturing of crystal growth, computer storage device, thermal power generation, gas turbine rotors etc. It is recognized fact that the nanofluids have pivotal role in the intensification of heat transfer. Thus we inspired to study nonlinear rotating flow problems in the presence of nanoparticles. It is noted that two-dimensional nonlinear flow problems subject to fixed frame in literature are much studied when compared with the three-dimensional nonlinear flow problems in rotating frame. Keeping such facts in mind the present thesis is organized for three-dimensional nonlinear flow problems of nanofluids subject to rotating frame. The present thesis is designed as follows. Chapter one has literature review of relevant previous published works and relations for conservations of mass, momentum, energy and concentration. Tensor forms for non-Newtonian fluids (Maxwell, Oldroyd-B and Jeffrey) are presented. Fundamental concept of optimal homotopy analysis method is included in this chapter. Chapter two elaborates three dimensional rotating flow of nanoliquid induced by a stretchable sheet. Darcy-Forchheimer porous space is considered. Thermophoretic diffusion and random motion aspects are retained. Heat and mass flux conditions are implemented at stretchable surface. Convergent series solutions have been derived for velocities, temperature and concentration. Optimal homotopy analysis technique (OHAM) is implemented for the solutions development. Further surface drag coefficients and heat and mass transfer rates are presented via plots. The contents of this chapter are published in International Journal of Numerical Methods for Heat and Fluid Flow 28 (2018) 2895-2915. Chapter three is the extension of chapter two for convective boundary conditions, heat generation/absorption, binary chemical reaction and activation energy. The nonlinear differential systems are numerically tackled by built-in shooting technique. Observations of this chapter are published in Journal of Thermal Analysis and Calorimetry 136 (2019) 1769-1779. Chapter four generalizes contents of chapter two for homogeneous-heterogeneous reactions. The results of this chapter are published in Physica Scripta 94 (2019) 115708. Chapter five addresses the Darcy-Forchheimer three dimensional flow of nanoliquid induced by an exponentially stretchable surface in rotating frame. Thermophoretic diffusion and random motion aspects are retained. Prescribed surface heat and mass fluxes are implemented at stretchable surface. The governing systems are solved numerically by built-in shooting technique. Moreover temperature, concentration, surface drag coefficients and local Nusselt and Sherwood numbers are graphically illustrated. The data of this chapter is published in Journal of Thermal Analysis and Calorimetry 136 (2019) 2087-2095. Chapter six illustrates the novel feature of entropy generation for three-dimensional rotating flow of nanoliquid with porous medium, velocity slip condition and activation energy. Thermophoretic dispersion and an irregular motion phenomena are also analyzed. Numerical solution is determined via efficient numerical method namely built-in shooting method. The obtained results for involved pertinent variables are examined through graphs for velocities, entropy generation, nano-concentration, temperature, skin-friction, local Nusselt number, Bejan number and local Sherwood numbers. Material of this chapter is submitted for publication in International Communications in Heat and Mass Transfer. Chapter seven extends the analysis of previous chapter for convective heat and mass conditions, magnetohydrodynamics (MHD), Joule heating and heat generation/absorption. Outcomes of this chapter are submitted for publication in Journal of Non-Equilibrium Thermodynamics. Chapter eight examines the impact of activation energy on three dimensional rotating flow of Maxwell nanoliquid with nonlinear radiative heat flux. Thermophoretic dispersion and irregular motion are investigated. Convective conditions of heat and mass are employed at the boundary. Shooting technique is implemented for solutions development. Influences of numerous emerging flow parameters on nano-concentration, temperature and mass and heat transfer rates are elaborated through graphs. The findings of this chapter have been submitted for publication in Journal of the Brazilian Society of Mechanical Sciences and Engineering. Chapter nine describes three dimensional rotating flow of an Oldroyd-B nanoliquid due to linearly extendable surface. Brownian movement and thermophoresis are explored. Thermal convective condition and a condition associated with zero nanomaterials flux are implemented at the boundary. The nonlinear differential expressions are solved through optimal homotopy analysis method (OHAM). Moreover velocities, temperature, concentration and transfer of heat rate are discussed graphically. The observations of this chapter have been published in Journal of the Brazilian Society of Mechanical Sciences and Engineering 41 (2019) 236. Chapter ten communicates three-dimensional rotating flow of Jeffrey nanoliquid in the presence of binary chemical reaction and activation energy. Impact of heat generation/absorption is also examined. Furthermore thermophoretic dispersion and irregular motion phenomena are investigated. Thermal convective and zero flux of nanoparticles conditions are accounted at the surface. Optimal homotopy analysis technique is utilized for solutions construction. Impacts of pertinent variables on velocities, nano-concentration, temperature and rate of heat transfer are interpreted through plots. The results of this research have been submitted for publication in Journal of Thermal Analysis and Calorimetry.