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Heat transfer is an important phenomenon in the industrial sector. Thus, the simulation is made to compute the distribution of heat in a rectangular channel in this paper. A heated rod is inserted at the center of the rectangular channel. The fluid flowing in the rectangular channel is considered to be a viscous fluid. Navier–Stokes equations of motion for laminar flow are used. The medium for the fluid motion is considered to be a porous medium. Heat transfer is computed for nonlinear two-dimensional incompressible and unsteady flows. The Fourier's law of heat conduction is used for the transmission of heat in the rectangular channel. The Finite Element Method (FEM) is applied to the solution of the problem. For different values of the permeability parameter, Prandtl number and Rayleigh number, the graphic solution for the velocity and temperature fields is shown. [ABSTRACT FROM AUTHOR]

In this study, the impact of Newtonian heating is incorporated into a two-dimensional ferrofluid. The flowing chemically reactive species of ferromagnetic fluid fluids. By virtue of this property, such fluids are necessary for heat transfer in engineering equipment and devices. The main focus of flowing fluids in these devices is to enhance the transfer of heat and decrease friction drag at the surface. Thus, the paper focuses on the analysis of the rate of heat transfer via Fourier's law. The fluid in the problem is taken to be a viscous fluid containing chemically reactive species. Chemically reactive species consist of two or more base fluids. Therefore, the main interest is in watching the heat transfer impacts on the ferromagnetic fluid. This is important in the presence of chemically reactive species. The results obtained are shown to be in excellent agreement in specific cases available in literature. [ABSTRACT FROM AUTHOR]

A heat exchanger is a device that transmits heat energy from one object to another, or within the same object. Examples of heat exchanger include a boiler, an oven and a cooker. Experimental techniques for testing these devices make it more costly and time-consuming. Consequently, computational fluid dynamics (CFD) can manage heat exchanger systems and their performance with ease. The actual impacts of what is being examined may then be predicted computationally which yields a precise output with approximate results. The designed geometry includes a rectangular duct with an inlet, outlet and two obstacles of equal height. The Navier–Stokes equations for the fluid flow are used. During the meshing process, the continuous geometric space of an item is divided into thousands or more forms, which helps to correctly identify the object's physical shape. The desired model is computed numerically. Finite volume method (FVM) is used to study the results at a low Reynolds number (around 2. 3 × 1 0 6). The goal is to theoretically analyze the transmission of heat and fluid resistance to the flow. The CFD findings with experimental data are compared to confirm the model predictions. A CFD model based on the FVM and experimental data from a flow cell is used to study how fluid moves through ducts. This study focuses on the pressure, velocity and temperature fields of a fluid moving through a rectangular duct. As the top wall fluid temperature rises, the temperature distribution changes. Increasing fluid flow declines the temperature distribution. Temperature distribution grows with duct heat flow. As the flow rate rises, so does dispersion. Furthermore, as flow rate and velocity distribution drop, pressure distribution rises. [ABSTRACT FROM AUTHOR]

The pursuit of superior working fluids for heat and mass transfer systems in the industry is on the rise, inspired by not only to maximize revenue but also to accommodate heat dissipation or chemical separation under extreme conditions. The addition of a small amount of nanoparticle, a product called nanofluid, has been initiated over the last decade. In particular, researchers have employed carbon nanotubes (CNTs) into conventional fluids as their preferred nanoparticles due to the merits of having a remarkable thermal conductivity compared to other nanoparticles. Here, we present a comprehensive and up to date review of this incredible fluid being applied in various heat transfer (convective and boiling) and mass transfer systems such as heat exchangers and separators. Other critical parameters associated with the practicality of the CNT nanofluids such as pumping power and efficiency are also discussed. We surveyed a remarkable range of results of some of the heat and mass transfer studies that strongly depend on the inherent CNT nanofluid characteristics and operating conditions such as CNT treatment, size, concentration, Reynolds number, and so on. A major conclusion that can be drawn from this review is the significantly higher heat transfer coefficient at lower pressure drop or pumping power of the CNT nanofluid compared to other nanofluids, which implied better thermal performance of the heat transfer system. Besides that, the concentration of CNT is the influential factor to achieve optimum boiling heat transfer while the mass transfer performance of the CNT nanofluid is moderately good against other nanofluids. Additionally, CNT treatment using covalent functionalization is crucial for the overall stability and performance of the CNT nanofluid. However, several issues that inhibit their widespread use such as possible corrosion-erosion in systems, lack of risk assessments, and high cost of CNT nanofluid must be thoroughly addressed in future studies. [ABSTRACT FROM AUTHOR]

Active and passive cooling are the two possible methods for removing heat. An active cooling system is the one that involves the use of energy as opposed to passive cooling that uses no energy. Passive cooling methods are cost effective and more reliable than active cooling due to the absence of moving parts. Microchannel heat sink is one of high-tech devices that have widely considered passive cooling methods especially for electronics cooling. In this paper, the use of passive cooling methods in microchannel heat sink is comprehensively discussed. This paper also present the effects of some important parameters such as the type of channel types, surface roughness, fluid additives, and Reynolds number on the rate of heat transfer in microchannel heat sink. Finally, the conclusions and important summaries were presented according to the data collected. [ABSTRACT FROM AUTHOR]

Nanofluids have gained significant attention in recent years due their great potential for heat transfer enhancement . The heat transfer of nanofluids can be numerically studied using a single-phase or two-phase approaches. The first assumes that the fluid phase and nanoparticles are in thermal equilibrium and move with the same velocity, while the second requires more computational effort but provides the possibility of understanding the behavior of both fluid phase and solid particles in the heat transfer mechanism. This paper reviews various computational approaches to predict fluid flow and heat transfer characteristics of nanofluids. The characteristics of single-phase and two-phase (volume of fluid, mixture, Eulerian–Lagrangian and Eulerian–Eulerian) approaches have been analyzed and discussed systematically. Latest development and recent researches related to the computational nanofluids are also given. [ABSTRACT FROM AUTHOR]

This paper reviewed the application of nanofluids in vehicle engine cooling system. So far, nanoparticles have been used in engine oil, transmission oil, and radiator coolant to enhance heat transfer removal from vehicle engine. The heat transfer performance of nanofluids has been reported to perform better compared to pure fluid. This review focused on the experimental and numerical studies by previous researchers and their suggested amount of nanoparticles for optimum performance in vehicle engine cooling system. Finally, the conclusions and important summaries were presented according to the data collected. [ABSTRACT FROM AUTHOR]

Theoretical analysis of heat transfer plays a vital role in updating the quality of heat exchanger products. Experiments cost more compared to computational costs. In this direction, this work is concerned with the unsteady and incompressible fluid flow with a rod inside a square cavity. The disturbance in the flow is induced by the motion of the top and bottom walls of the cavity. The maximum fluid flow will arise, which will help in reducing the temperature of the heated wall or rod in any physical situation. A single wall is considered to be heated, which produces heat in the neighboring fluid layers. A rod is placed to reduce the motion of the heated fluid coming from the heated wall at a high-temperature. The transmission of thermal energy along with fluid flow is carried out using the energy equation and the Navier–Stokes equation of motion, respectively. These equations are transformed to dimensionless form by appropriate parametrization and solved using the finite element method for different parameters such as Rayleigh number and Prandtl number, temperature and velocity fields and are presented graphically [ABSTRACT FROM AUTHOR]

The article focuses on the mixed convective flow of Ag–ethylene glycol nanofluid. The analysis is carried out for a cavity having center as heated. The relatively moving side walls of cavity are retained at low constant temperature while constant heat source is examined in the bottom wall. The rest of the bottom and top walls remain insulated. Cattaneo–Christov heat flux is implemented in the analysis of heat transfer. Heat transfer rate is dig out for the case of Fourier's heat flux, as for the case of Cattaneo–Christov heat flux it gives implicit expression, which is difficult to analyze and simplify. The problem is analyzed numerically via projection method. Higher heat transfer is observed for the Fourier's law as compare to Cattaneo–Christov heat flux. The results are expressed by isotherms, streamlines, velocity field, and average Nusselt numbers. • Nanoparticles in a viscous flow is studied. • The impact of thermal relaxation time is considered. • Comparison of Fourier's and Cattaneo–Christov heat flux is presented. • Thermal relaxation declines the transfer of heat. [ABSTRACT FROM AUTHOR]

The foremost aim of the present paper is to explore the impact of heat transport phenomenon in a ferrofluid via magnetic dipole. Three distinct ferrite nanoparticles are discussed in the present study with water as the base fluid. Magnetic dipole existing in ferrite nanoparticles plays a significant role in controlling the momentum and thermal boundary layers. The partial differential equations (PDEs) are changed into nonlinear coupled ordinary differential equation (ODEs) by utilising similar transformations. Flow occurs due to linear stretching sheet. For the evaluation of heat flux, Fourier’s law of heat conduction is employed. Effects of rising parameters on the magneto-thermomechanical coupling are examined numerically. The results indicate that the property of magneto-thermomechanical cooperation slows the motion of liquid particles, and accordingly, strengthen the heat transfer rate at the surface and skin friction coefficient. Further, Nusselt number enhances with larger solid volume fraction. A magnificent comparison with accessible results for definite cases has been made. [ABSTRACT FROM AUTHOR]

The performance of friction drag, heat transfer rate, and mass transfer is illustrated the in boundary layer flow region via density of motile microorganisms. Magnetic dipole in presence of Curie temperature and density of motile microorganisms plays important role in stabilizing and controlling the momentum and thermal boundary layers. In this direction, the characteristics of the magnetic dipole on the suspensions of motile microorganisms in the flow of ferrofluid are incorporated. Heat flux in the suspensions of motile microorganisms and at the surface is computed via Fourier's law of heat conduction. Characteristics of sundry physical parameter on the ferrohydrodynamic, thermal energy, mass transfer, and bioconvection are computed numerically and analytically. It is depicted that an enhancement in thermal Rayleigh number results in the reduction of friction drag, thereby enhances the heat transfer rate and Sherwood number at the surface, while the local density of motile microorganisms enhance for larger values of bioconvection Lewis number. Further, it is characterized that bioconvection Rayleigh number has increasing behavior on the heat transfer in the boundary layer. Comparison with available results are found in an excellent agreement. • Heat transport phenomenon is depicted in motile micro-organisms. • Thermal Rayleigh number results in the reduction of friction drag. • Velocity reduces and the temperature field enhances for β_{f}. • The wall shear stress of the motile micro-organisms reduces. • The fast reduction in heat transfer rate is observed. [ABSTRACT FROM AUTHOR]

Nanofluid, an advanced type of fluid containing small quantity of nanoparticles (usually less than 100 nm), has been proven to provide more efficient heat transfer compared to conventional fluids. The dispersion of a small amount of solid nanoparticles in conventional fluids such as water or ethylene glycol changes their thermal conductivity remarkably. Recently, nanofluid has been used as a heat transfer fluid to enhance the performance of solar collector devices. This paper reviews recent progress and applications of nanofluids in stationary solar collectors. In addition to reviewing the efficiency of solar collectors which use nanofluids, the paper also discusses the impact of nanofluid usage in solar collector based on economic and environmental viewpoints. Finally, the challenges and future trends related to the application of nanofluids in thermal solar collector is discussed. [ABSTRACT FROM AUTHOR]

In this article, turbulent flow characteristic of nanofluids is thoroughly reviewed. Turbulent flows have unique characteristics and are preferred in many industrial applications. Therefore, this paper reviews different techniques used to enhance heat transfer using nanofluids within turbulent regime. This paper also presents the effects of some important parameters such as nanoparticle type, nanoparticles concentration, and Reynolds number on heat transfer rate. Studies on numerical techniques are also discussed. Finally, the conclusions and important summaries are presented according to the data collected. [ABSTRACT FROM AUTHOR]

This article deals with numerical analysis of two-dimensional viscous fluid in modified square duct. A rectangular obstacle with constant temperature at walls is placed inside it. Flow duct is depicted in Figs. 1 and 2. Influence of Prandtl number and geometry on heat transfer of working fluid is studied in two cases. Computation for the present model is made in commercial package ANSYS-Fluent. Calculations are carried at two different values of Reynolds numbers i.e., Re 40 and 200 for each of the cases. Liquid water (H 2 0) and Liquid Aniline (C 6 H 5 NH 2) are taken as working fluids. Stream functions, isotherms, vorticity, velocity and pressure profiles are examined. Graphical data for C f and Nu is presented to analyze the effect of Reynolds number and Prandtl number on heat transfer. Thermal boundary layers are discussed in each of the cases. It is shown that heat transfer has high dependance on Reynolds number and Prandtl number. Geometry of the problem has noticeable effect on heat transfer. [ABSTRACT FROM AUTHOR]