Shashikumar N.S., B.J. Gireesha, B. Mahanthesh, Prasannakumara B.C. and Ali J. Chamkha
Outstanding features such as superior electrical conductivity and thermal conductivity of alloy nanoparticles with working fluids make them ideal materials to be used as coolants…
Abstract
Purpose
Outstanding features such as superior electrical conductivity and thermal conductivity of alloy nanoparticles with working fluids make them ideal materials to be used as coolants in microelectromechanical systems (MEMSs). This paper aims to investigate the effects of different alloy nanoparticles such as AA7075 and Ti6Al4V on microchannel flow of magneto-nanoliquids with partial slip and convective boundary conditions. Flow features are explored with the effects of magnetism and nanoparticle shape. Heat transport of fluid includes radiative heat, internal heat source/sink, viscous and Joule heating phenomena.
Design/methodology/approach
Suitable dimensionless variables are used to reduce dimensional governing equations into dimensionless ordinary differential equations. The relevant dimensionless ordinary differential systems are computed numerically by using Runge–Kutta–Fehlberg-based shooting approach. Pertinent results of velocity, temperature, entropy number and Bejan number for assorted values of physical parameters are comprehensively discussed. Also, a closed-form solution is obtained for momentum equation for a particular case. Analytical results agree perfectly with numerical results.
Findings
It is established that the entropy production can be improved with radiative heat, Joule heating, convective heating and viscous dissipation aspects. The entropy production is higher in the case of Ti6Al4V-H2O nanofluid than AA7075-H2O. Further, the inequality Ns(ξ)Sphere > Ns(ξ)Hexahedran > Ns(ξ)Tetrahydran > Ns(ξ)Column > Ns(ξ)Lamina holds true.
Originality/value
Effects of aluminium and titanium alloy nanoparticles in microchannel flows by using viscous dissipation and Joule heating are investigated for the first time. Flow features are explored with the effects of magnetism and nanoparticle shape. The results for different alloy nanoparticles such as AA7075 and Ti6Al4V have been compared.
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N.S. Shashikumar, Madhu Macha, B.J. Gireesha and Naikoti Kishan
In recent years, microfluidics has turned into a very important region of research because of its wide range of applications such as microheat exchanger, micromixers fuel cells…
Abstract
Purpose
In recent years, microfluidics has turned into a very important region of research because of its wide range of applications such as microheat exchanger, micromixers fuel cells, cooling systems for microelectronic devices, micropumps and microturbines. Therefore, in this paper, micropolar nanofluid flow through an inclined microchannel is numerically investigated in the presence of convective boundary conditions. Heat transport of fluid includes radiative heat, viscous and Joule heating phenomena.
Design/methodology/approach
Governing equations are nondimensionalized by using suitable dimensionless variables. The relevant dimensionless ordinary differential systems are solved by using variational finite element method. Detailed computations are done for velocity, microrotation and temperature functions. The influence of various parameters on entropy generation and the Bejan number is displayed and discussed.
Findings
It is established that the entropy generation rate increased with both Grashof number and Eckert number, while it decreased with nanoparticle volume fraction and material parameter. Temperature is decreased by increasing the volume fraction of Ag nanoparticle dispersed in water.
Originality/value
According to the literature survey and the best of the author’s knowledge, no similar studies have been executed on micropolar nanofluid flow through an inclined microchannel with effect of viscous dissipation, Joule heating and thermal radiation.
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Shashikumar N.S., Gireesha B.J., B. Mahanthesh and Prasannakumara B.C.
The microfluidics has a wide range of applications, such as micro heat exchanger, micropumps, micromixers, cooling systems for microelectronic devices, fuel cells and…
Abstract
Purpose
The microfluidics has a wide range of applications, such as micro heat exchanger, micropumps, micromixers, cooling systems for microelectronic devices, fuel cells and microturbines. However, the enhancement of thermal energy is one of the challenges in these applications. Therefore, the purpose of this paper is to enhance heat transfer in a microchannel flow by utilizing carbon nanotubes (CNTs). MHD Brinkman-Forchheimer flow in a planar microchannel with multiple slips is considered. Aspects of viscous and Joule heating are also deployed. The consequences are presented in two different carbon nanofluids.
Design/methodology/approach
The governing equations are modeled with the help of conservation equations of flow and energy under the steady-state situation. The governing equations are non-dimensionalized through dimensionless variables. The dimensionless expressions are treated via Runge-Kutta-Fehlberg-based shooting scheme. Pertinent results of velocity, skin friction coefficient, temperature and Nusselt number for assorted values of physical parameters are comprehensively discussed. Also, a closed-form solution is obtained for momentum equation for a particular case. Numerical results agree perfectly with the analytical results.
Findings
It is established that multiple slip effect is favorable for velocity and temperature fields. The velocity field of multi-walled carbon nanotubes (MWCNTs) nanofluid is lower than single-walled carbon nanotubes (SWCNTs)-nanofluid, while thermal field, Nusselt number and drag force are higher in the case of MWCNT-nanofluid than SWCNT-nanofluid. The impact of nanotubes (SWCNTs and MWCNTs) is constructive for thermal boundary layer growth.
Practical implications
This study may provide useful information to improve the thermal management of microelectromechanical systems.
Originality/value
The effects of CNTs in microchannel flow by utilizing viscous dissipation and Joule heating are first time investigated. The results for SWCNTs and MWCNTs have been compared.
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This paper aims to investigate the role of shapes of containers (nine different containers) on entropy generation minimization involving identical cross-sectional area (1 sq…
Abstract
Purpose
This paper aims to investigate the role of shapes of containers (nine different containers) on entropy generation minimization involving identical cross-sectional area (1 sq. unit) in the presence of identical heating (isothermal). The nine containers are categorized into three classes based on their geometric similarities (Class 1: square, tilted square and parallelogram; Class 2: trapezoidal type 1, trapezoidal type 2 and triangular; Class 3: convex, concave and curved triangular).
Design/methodology/approach
Galerkin finite element method is used to solve the governing equations for a representative fluid (engine oil: Pr = 155) at Ra = 103–105. In addition, finite element method is used to solve the streamfunction equation and evaluate the entropy generation terms (Sψ and Sθ). Average Nusselt number (
Findings
Based on larger
Practical implications
Comparison of entropy generation, intensity of thermal mixing (
Originality/value
This study depicts that entropy generation associated with the convection process can be reduced via altering the shapes of containers to improve the thermal performance or efficiency for processing of identical mass with identical heat input. The comparative study of nine containers elucidates that the values of local maxima of Sψ (Sψ,max), Sθ (Sθ,max) and magnitude of Stotal vary with change in shapes of the containers (Classes 1–3) at fixed Pr and Ra. Such a comparative study based on entropy generation minimization on optimal heating during convection of fluid is yet to appear in the literature. The outcome of this study depicts that containers with curved walls are instrumental to optimize entropy generation with reasonable thermal processing rates.
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S. Sindhu, B.J. Gireesha and G. Sowmya
The influence of radiation on nanoliquid flow through a vertical microchannel in the presence of heat source is examined. This study aims to investigate the efficiency of…
Abstract
Purpose
The influence of radiation on nanoliquid flow through a vertical microchannel in the presence of heat source is examined. This study aims to investigate the efficiency of multi-walled carbon nanotube (MWCNT) considering water and engine oil as base fluid.
Design/methodology/approach
Nondimensional variables are used to obtain the dimensionless physical model. The solutions are computed numerically via Runge–Kutta–Fehlberg integration scheme.
Findings
It is established that (knf/kf)Lamina > (knf/kf)Column > (knf/kf)Tetrahedron > (knf/kf)Hexahedron > (knf/kf)Sphere.
Originality/value
Thermal conductivity of MWCNT is analyzed using different models. Also, it is remarked that Xue model exhibits higher thermal conductivity for MWCNT compared to Maxwell model, Yu-Choi model and Hamilton-Crosser model.
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Anantha Kumar K., Ramana Reddy J.V., Sugunamma V. and N. Sandeep
The purpose of this paper is to propose the knowledge of thermal transport of magneto hydrodynamic non-Newtonian fluid flow over a melting sheet in the presence of exponential…
Abstract
Purpose
The purpose of this paper is to propose the knowledge of thermal transport of magneto hydrodynamic non-Newtonian fluid flow over a melting sheet in the presence of exponential heat source.
Design/methodology/approach
The group of PDE is mutated as dimension free with the assistance of similarity transformations and these are highly nonlinear and coupled. The authors solved the coupled ODE’s with the help of fourth-order Runge–Kutta based shooting technique. The impact of dimensionless sundry parameters on three usual distributions of the flow was analyzed and bestowed graphically. Along with them friction factor, heat and mass transfer rates have been assessed and represented with the aid of table.
Findings
Results exhibited that all the flow fields (velocity, concentration and temperature) are decreasing functions of melting parameter. Also the presence of cross-diffusion highly affects the heat and mass transfer performance.
Originality/value
Present paper deals with the heat and mass transfer characteristics of magnetohydrodynamics flow of non-Newtonian fluids past a melting surface. The effect of exponential heat source is also considered. Moreover this is a new work in the field of heat transfer in non-Newtonian fluid flows.
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Thameem Hayath Basha, Sivaraj Ramachandran and Bongsoo Jang
The need for precise synthesis of customized designs has resulted in the development of advanced coating processes for modern nanomaterials. Achieving accuracy in these processes…
Abstract
Purpose
The need for precise synthesis of customized designs has resulted in the development of advanced coating processes for modern nanomaterials. Achieving accuracy in these processes requires a deep understanding of thermophysical behavior, rheology and complex chemical reactions. The manufacturing flow processes for these coatings are intricate and involve heat and mass transfer phenomena. Magnetic nanoparticles are being used to create intelligent coatings that can be externally manipulated, making them highly desirable. In this study, a Keller box calculation is used to investigate the flow of a coating nanofluid containing a viscoelastic polymer over a circular cylinder.
Design/methodology/approach
The rheology of the coating polymer nanofluid is described using the viscoelastic model, while the effects of nanoscale are accounted for by using Buongiorno’s two-component model. The nonlinear PDEs are transformed into dimensionless PDEs via a nonsimilar transformation. The dimensionless PDEs are then solved using the Keller box method.
Findings
The transport phenomena are analyzed through a comprehensive parametric study that investigates the effects of various emerging parameters, including thermal radiation, Biot number, Eckert number, Brownian motion, magnetic field and thermophoresis. The results of the numerical analysis, such as the physical variables and flow field, are presented graphically. The momentum boundary layer thickness of the viscoelastic polymer nanofluid decreases as fluid parameter increases. An increase in mixed convection parameter leads to a rise in the Nusselt number. The enhancement of the Brinkman number and Biot number results in an increase in the total entropy generation of the viscoelastic polymer nanofluid.
Practical implications
Intelligent materials rely heavily on the critical characteristic of viscoelasticity, which displays both viscous and elastic effects. Viscoelastic models provide a comprehensive framework for capturing a range of polymeric characteristics, such as stress relaxation, retardation, stretching and molecular reorientation. Consequently, they are a valuable tool in smart coating technologies, as well as in various applications like supercapacitor electrodes, solar collector receivers and power generation. This study has practical applications in the field of coating engineering components that use smart magnetic nanofluids. The results of this research can be used to analyze the dimensions of velocity profiles, heat and mass transfer, which are important factors in coating engineering. The study is a valuable contribution to the literature because it takes into account Joule heating, nonlinear convection and viscous dissipation effects, which have a significant impact on the thermofluid transport characteristics of the coating.
Originality/value
The momentum boundary layer thickness of the viscoelastic polymer nanofluid decreases as the fluid parameter increases. An increase in the mixed convection parameter leads to a rise in the Nusselt number. The enhancement of the Brinkman number and Biot number results in an increase in the total entropy generation of the viscoelastic polymer nanofluid. Increasing the strength of the magnetic field promotes an increase in the density of the streamlines. An increase in the mixed convection parameter results in a decrease in the isotherms and isoconcentration.
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This paper aims to focus on the steady state flow of nanoliquid through microchannel with the aid of internal heat source and different shapes of nanoparticle. The influence of MoS…
Abstract
Purpose
This paper aims to focus on the steady state flow of nanoliquid through microchannel with the aid of internal heat source and different shapes of nanoparticle. The influence of MoS2 and TiO2 particles of nano size on flow and thermal fields is examined. The governing equations are modelled and then solved numerically. The obtained physical model is nondimensionalized using dimensionless quantities. The nondimensional equations are treated with numerical scheme. The outcome of the current work is presented graphically. Diverse substantial quantities such as entropy generation, Bejan number and Nusselt number for distinct parameters are depicted through graphs. The result established that nanoparticle of blade shape acquires larger thermal conductivity. Entropy analysis is carried out to explore the impact of various parameters such as nanoparticle volume fraction, magnetic parameter, radiation parameter and heat source parameter.
Design/methodology/approach
The resultant boundary value problem is converted into initial value problem using shooting scheme. Then the flow model is resolved using Runge-Kutta-Fehlberg-Fourth-Fifth order technique.
Findings
It is emphasized that entropy generation for the fluid satisfies N(ζ)(TiO2−water) > N(ζ)(MoS2−water). In addition to this, it is emphasized that N(ζ)sphere > N(ζ)brick > N(ζ)cylinder > N(ζ)platelet > N(ζ)blade. Also, it is obtained that blade-shaped nanoparticle has higher thermal conductivity for both MoS2 and TiO2.
Originality/value
Shape effects on Molybdenum disulphide and TiO2 nanoparticle in a microchannel with heat source is examined. The analysis of entropy shows that N(ζ)(TiO2−water) > N(ζ)(MoS2−water).
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B.J. Gireesha and A. Roja
Microfluidics is one of the interesting areas of the research in thermal and engineering fields due to its wide range of applications in a variety of heat transport problems such…
Abstract
Purpose
Microfluidics is one of the interesting areas of the research in thermal and engineering fields due to its wide range of applications in a variety of heat transport problems such as micromixers, micropumps, cooling systems for microelectromechanical systems (MEMS) micro heat exchangers, etc. Lower cost with better thermal performance is the main objective of these devices. Therefore, in this study, the entropy generation in an electrically conducting Casson fluid flow through an inclined microchannel with hydraulic slip and the convective condition hves been numerically investigated. Aspects of viscous dissipation, natural convection, joule heating, magnetic field and uniform heat source/sink are used
Design/methodology/approach
Suitable non-dimensional variables are used to reduce the non-linear system of ordinary differential equations, and then this system is solved numerically using Runge-Kutta-Fehlberg fourth fifth order method along with shooting technique. The obtained numerical solutions of the fluid velocity and temperature are used to characterize the entropy generation and Bejan number. Also, the Nusselt number and skin friction coefficient for various values of parameters are examined in detail through graphs. The obtained present results are compared with the existing one which is perfectly found to be in good agreement.
Findings
It is established that the production of the entropy can be improved with the aspects of joule heating, viscous dissipation and internal heat source/sink. The entropy generation enhances for increasing values of Casson Parameter
Originality/value
Entropy generation analysis on MHD Casson fluid flow through an inclined microchannel with the aspects of convective, Joule heating, viscous dissipation, magnetism, hydraulic slip and internal heat source/sink has been numerically investigated.