Heat Transfer Of Nanofluid Flow Research Articles

Expression of Concern: Effects of magnetic field on natural convective heat transfer of nanofluid flow in a two-dimensional rectangular cavity in the presence of constant-temperature triangular blades on the bottom wall

Expression of Concern: Effects of magnetic field on natural convective heat transfer of nanofluid flow in a two-dimensional rectangular cavity in the presence of constant-temperature triangular blades on the bottom wall

Expression of Concern: Effect of the length and thickness of three constant temperature baffles on the natural convection heat transfer of nanofluid flow inside an enclosure affected by a magnetic field

Expression of Concern: Effect of the length and thickness of three constant temperature baffles on the natural convection heat transfer of nanofluid flow inside an enclosure affected by a magnetic field

Two-phase analysis of heat transfer of nanofluid flow in a wavy channel heat exchanger: A numerical approach

The heat transfer improvement by using CuO/water nanofluid (NF) in a wavy channel is evaluated numerically using the turbulent two-phase mixture and the κ - ε models. The numerical work is a 2-dimensional model created and analyzed in Gambit and Ansys Fluent software, respectively. The flow Reynolds (Re) numbers of 8000 to 40,000, wavelength ranging from 0 to 0.4 m, and solid volume fraction (SVF) of 0 % to 4 % are investigated. In all cases, a constant heat flux of q′′=5000 W/m2 is applied on the outer surface of the heat exchanger. The heat transfer and fluid flow were analyzed by the flow visualization method and heat transfer evaluation indexes. The results show that by increasing the Re number, the vortices increase and more turbulence are generated in the vicinity of the waves near the channel inlet. As the amplitude of the channel waves increased, the velocity at the top of the wave increased, and the resulting pressure gradient behind the wave is intensified and the reverse flow is generated. The improving effect of using NF is more prominent where the effect of other enhancing factors is weak. For wall amplitude of 0.1m, by increasing the SVF from 1 to 4% the average Nu number (Nuavg) increased by 35% and 22% in Re = 8,000 and 40,000, respectively.

Retraction notice: Numerical investigation on turbulent convective heat transfer of nanofluid flow in a square cross-sectioned duct

Retraction notice: Numerical investigation on turbulent convective heat transfer of nanofluid flow in a square cross-sectioned duct

Influence of cross baffle on heat transfer of nanofluid flow inside circular pipe in existence of electromagnetic field: Computational study

The usage of electromagnetic sources for the improvement of the heat transfer of ferrofluid is an efficient method in heat exchangers. In this article, the effects of the non-uniform electromagnetic field on the thermal characteristics of the nanofluid with 4 % nanoparticles of Fe3O4 streaming inside the pipe with a double cross barrier are extensively investigated. To simulate the nanofluid flow, Computational Fluid Dynamic is applied and a three-dimensional model is chosen to reveal the main effects of the electromagnetic field on the thermal efficiency of the nanofluid flow. The main novelty of this work is related to the application of the cross baffle and non-uniform magnetic field for the heat transfer improvements. The achieved results show that the existence of the electromagnetic field and cross barrier facilitates the production of the vortex inside the pipe. Therefore, the thermal layer diffusion into the stream more efficiently, and the thermal efficiency of nanofluid is improved. The influence of magnetic field intensity also shows that increasing the thermal efficiency is a direct function of magnetic source intensity.

Investigating the Impact of Flow Profile on Heat Transfer in Nanofluid Flow: A Numerical Study

Assessing the profitability of an energy system requires careful consideration of various factors, including fluid characteristics, geometry shape, and operating conditions. This study investigates the influence of sinusoidal rib shapes, with different space ratios (e/b) ranging from 0 to 1, on heat transfer in nanofluid flow. The channel's upper surface is subjected to a uniform heat flux, employing Al2O3 nanofluid as the working fluid and varying Reynolds numbers from 5000 to 20000. Additionally, the effect of aluminum nanoparticle volume fraction, ranging from 0 to 6%, is analyzed. Simulation results indicate that the performance of the corrugated surface in the channel is significantly influenced by rib shapes and their geometrical parameters. The highest Performance Evaluation Criteria (PEC) index is achieved for ribs with a space ratio (e/b) of 0 at Reynolds number of 5000 and a volume fraction of 6% nanoparticles. Furthermore, the average Nusselt number shows an increasing trend with higher particle volume fraction and Reynolds numbers.

Enhancement of Heat Transfer in Nanofluid Flow Through Elbows with Varied Cross-Sections: A Computational Study

Enhancement of Heat Transfer in Nanofluid Flow Through Elbows with Varied Cross-Sections: A Computational Study

Study of Bejan number and entropy generation for mixed convection of nanofluid flow inside a chamber under an inclined magnetic field

Examination of the efficiency and losses in heat exchange devices is pivotal. Therefore, the entropy generation (EYG) and Bejan number (Be) of mixed convective heat transfer of nanofluid flow in a rectangular cavity (RCY) are evaluated in this study. Five baffles are placed at the lower hot wall of the RCY. The cold upper wall moves and causes forced convection flow of nanofluid. The magnetic field (MFD) at different angles affects the nanofluid when the Hartmann number (Ha) changes from 10 to 40. The length of stepped baffles is changed, and the values of frictional EYG, thermal EYG, and total EYG are estimated. The simulations are done using the LBM and an in-house code. The results demonstrate that the improvement in Ha decreases the amount of frictional EYG, thermal EYG, total EYG, and Be. The total EYG and Be also increase as the MFD angle is increased. The increment in the Richardson number (Ri) reduces the frictional EYG and total EYG (61.8 %) and increases the value of thermal EYG. Enhancing the length of the baffles intensifies the amount of Be and total EYG (3.4 %) and thermal EYG, but decreases the frictional EYG.

MHD Free Convection Heat Transfer in Nano-Fluid Flow in Square Porous Cavity of TiO2 Nanoparticles with Base Fluid Engine Oil

MHD Free Convection Heat Transfer in Nano-Fluid Flow in Square Porous Cavity of TiO2 Nanoparticles with Base Fluid Engine Oil

Two-phase analysis of heat transfer of nanofluid flow in a cavity in the presence of a magnetic field, heating element, and a porous medium: A numerical approach

By increasing the efficiency of heating systems, more heat flux can be transferred in a certain dimension, thus lowering the operating temperature, or a specific heat flux can be transferred using a smaller heat exchanger. In this study, the flow of a Newtonian nanofluid in a square cavity containing a heating element filled with a porous medium is simulated under the effect of a uniform magnetic field in different rotation angles. The finite volume method (FVM) and two-phase mixture model were used. Water is used as the base fluid and Al2O3 nanoparticles are used as the solid nanoparticles. The heating element inside the cavity, which is filled with porous medium with porosity percentage ε moves up or down to the width of the element. The fields of velocity, streamlines, and temperature are physically plotted, and Nusselt number and entropy generations diagrams are plotted. The results show that the change in the angle of the cavity and the change in position of the heating element on the hot wall have significant effects on the physical patterns. Other results indicate that with increasing volume fraction of nanoparticles and Rayleigh number (Ra), Nusselt number increases. Also, increasing the volume fraction of nanoparticles and Hartmann number (Ha) decreases the entropy generation due to heat transfer and increases the entropy generation due to friction. Also, it was found that in the cavity without a heating element, with increasing θ, the amount of local velocity increases in more places; so that, in case A and θ=90°, it reaches its maximum value in the cavity without a heating element. As can be seen, by placing the heating element at θ=0°, the maximum local velocity occurs above the heating element. Gradually, this value decreases with increasing the angle of the cavity filled with the porous medium relative to the x-axis to reach its minimum value in the cavity with θ=90°.

Effects of magnetic field on natural convective heat transfer of nanofluid flow in a two-dimensional rectangular cavity in the presence of constant-temperature triangular blades on the bottom wall

The simulation of the natural convective heat transfer (HTR) of nanofluid (NFD) flow in a two-dimensional rectangular cavity is performed in this paper. A magnetic field (MFD) is placed close to the cavity and the NFD. The top wall of the cavity is cold, and the side walls are insulated. Three isothermal triangular blades are mounted on the bottom wall at the same temperature as the wall. By changing the height of one of these blades from 0.1 to 0.7 and changing the location of this blade, three HTR models are estimated. Lattice Boltzmann method (LBM) and an in-house code are used for the simulations. The findings show that including the MFD lowers the Nu. The Nu is reduced with the Ha. Enhancing the length of the blades intensifies the average Nu for three studied models so that an increment in the blade length from 0.1 to 0.7 enhances the Nu from 9.3% to 18.5%, respectively. For the blade length of 0.1 and 0.3, model 2 has the maximum Nu, while model 1 has the maximum Nu for the blade length of 0.5 and 0.7.

Effect of the length and thickness of three constant temperature baffles on the natural convection heat transfer of nanofluid flow inside an enclosure affected by a magnetic field

This article examines the natural convection heat transfer (CNHT) in a two-dimensional square enclosure using the LBM. Nanofluid (NFD) is placed inside the enclosure and a magnetic field (MGF) is applied to the enclosure and NFD. The MGF has inclination angles ranging from 0 to 75° and its effect on the flow field and heat transfer (HTR) is evaluated. Also, the magnitude of the MGF varies by changing the Hartmann number (Ha) from 0 to 40. The left and right walls are hot and cold, respectively, and the top and bottom ones are insulated. Three baffles are placed on the hot wall, whose thickness is changed from 0.5 to 0.15 and their length is changed from 0.1 to 0.3. The results demonstrate that maximum HTR occurs on the upper part of the cold wall. The enhancement in the Ha reduces the value of Nu, and the increment of the inclination angle of the MGF enhances the value of Nu on the cold wall. An intensification in the thickness of the baffles (TOB) weakens the CNHT in the enclosure and thus reduces the amount of HTR. Also, enhancing the length of the baffles (LOB) weakens the vortex inside the enclosure.

Influence of non-uniform magnetic field on the thermal efficiency hydrodynamic characteristics of nanofluid in double pipe heat exchanger

Enhancement of the heat transfer rate inside the double pipe heat exchangers is significant for industrial applications. In present work, the usage of non-uniform magnetic field on the heat transfer rate of the nanofluid flow streamed inside double pipe heat exchangers are comprehensively studied. Computational technique of CFD is used for the visualization of the nanofluid hydrodynamic in existence of the magnetic source. Influences of the magnetic intensity and nanofluid velocity on the heat transfer are also presented. Simple algorithm is used for the modeling of the incompressible nanofluid flow with addition of magnetic source. Presented results show that magnetic source intensifies the formation of the circulation in the gap of the inner tube and consequently, heat transfer is enhanced in our domain. Comparison of different geometries of tube reveals that the triangle tube is more efficient for improvement of the heat transfer of nanofluid flow. Our results indicate that heat transfer in the tube with triangular shape is more than other configurations and its performance is 15% more than smooth tube.

Convective flow over heat dissipating fins for application of electronic package cooling using curved boundary scheme lattice Boltzmann method

PurposeThe purpose of this study is to address a problem in cooling of an electronic package where the dissipating fins transfer the extra heat energy from the heat source (i.e. electronic devices) to the heat sink (i.e. environment). To this end, the convective heat transfer of nanofluid flow over dissipating fins is simulated using a numerical approach, whereas the properties of nanofluid are evaluated based on the experimental measurements and used in the numerical process.Design/methodology/approachTo simulate the convective flow, the lattice Boltzmann method is used. Also, the curved boundary scheme is used to enhance the capability of lattice Boltzmann method (LBM) in the simulation of natural convection in curved boundaries. In addition, the second law analysis is used based on total and local approaches.FindingsTo improve the cooling performance of fins, a modern technique is used, which is using of nanofluid. For this purpose, samples of SiO2-liquid paraffin with mass fractions of 0.01, 0.05, 0.1, 0.5 and 1 (Wt.%) in a temperature range of 25–60 °C are provided, and the required thermal and physical properties of samples including thermal conductivity and dynamic viscosity are measured during experimental work. The extracted results are used in the numerical simulations using derived correlations.Originality/valueThe originality of the present work is using a modern numerical method in the investigation of an engineering application and combining it with experimental data.

Modeling of Soret and Dufour’s Convective Heat Transfer in Nanofluid Flow Through a Moving Needle with Artificial Neural Network

Modeling of Soret and Dufour’s Convective Heat Transfer in Nanofluid Flow Through a Moving Needle with Artificial Neural Network

Comparison of single-phase Newtonian and non-Newtonian nanofluid and two-phase models for convective heat transfer of nanofluid flow in backward-facing step

The aim is to investigate the application of nanofluids for improving the heat transfer in a backward-facing step channel. Numerical simulations are performed using single-phase models for both Newtonian and non-Newtonian fluids in the Reynolds number range 280–470. Constant and temperature-dependent thermo-physical properties of different volume fractions (0–4%) of nanoparticles are considered. The thermal enhancement of the nanofluids within the channel is analyzed and compared with the experimental data. A detailed comparison of different CFD models is established. Numerical results are obtained with two types of single-phase models (Newtonian and non-Newtonian) and three types of two-phase models (mixture, volume of fluid (VOF), Eulerian) and compared with experimental results obtained for the Nusselt number. The finite volume method is used to solve the system of governing partial differential equations describing the steady-state, two-dimensional, laminar, mixed convective flow in a micro backward facing step channel with uniform heat flux. The single-phase and two-phase models predict practically equivalent hydrodynamic fields, but significantly different thermal fields are observed in our results. The performance efficiency coefficient (PEC) is determined using single-phase and two-phase methods for Al2O3-water nanofluids at different Reynolds numbers to investigate their thermal performance.

Significance of Stefan Blowing and Convective Heat Transfer in Nanofluid Flow Over a Curved Stretching Sheet with Chemical Reaction

The applications of fluid flow with Newtonian heating effect include conjugate heat conveyance around fins, petroleum industry, and heat exchangers designing. Motivated from these applications, an attempt has been made to analyze the stream of viscous nanomaterial subjected to a curved stretching sheet. Also, heat and mass transport mechanism due to a chemical reaction, Brownian and thermophoresis motion are discussed. The equations of the mathematical model are formulated by considering the Newtonian heating and Stefan blowing conditions at the boundary. These modelled equations are then changed to a system of nonlinear equation involving ordinary derivatives of a function by means of suitable similarity transformations. Further, shooting technique with Runge-Kutta-Fehlberg-45 process is utilized to solve the reduced equations. Outcomes disclose that, the gain in Stefan blowing parameter escalates the liquid velocity. The intensification in chemical reaction rate parameter deteriorates the concentration gradient. The rise in Schmidt number and thermophoresis parameter drops the mass transfer rate. The increased values of Newtonian heating parameter with respect to thermophoresis parameter decays the heat transport rate.

Flow Analysis and Heat Transfer of Nanofluid Flow in Different Geometries: A Review with Focus on Recent Development

In a thermo-dynamical system loss of energy takes the centre of attention. Laws of thermodynamics stated that energies of the system cannot be lost, but this energy could be engaged to perform useful work, or wastefully lost in form of rises in temperature of the system. It is eminent to control the factors which act in rising values of loss in energy. Nanofluids uses nanosized particles with very high thermal conductivity uniformly distributed in base fluids which increases the conductivity of the base fluid ridiculously. Nanofluid play a vital role in reducing the loss of energy and improve heat conduction. An effort has been made in this paper is to carry out an extensive review of the literature regarding Nanofluid in recent years. Some basic components and properties of nanofluids are deeply elaborated in this article. Preparation of nanofluids perform a very significant role in recent decades. The new advanced results in nanofluids helps the reader to clarify their concepts are argued using two major dynamical models.

Heat transfer analysis of nanofluid flow in a channel with non-parallel walls

The aim of the current investigation is to explore the heat transfer of nanofluid flow in a channel with non-parallel walls. Two different nanoparticles, namely, Cu and Ag, with water as the base fluid are considered. The equations governing the flow are obtained using an appropriate similarity transform and solved analytically with the optimal homotopy asymptotic method (OHAM). Here, OHAM was first used to solve the problem to ensure a much more rapid convergence of the solution only after one iteration, with high efficiency. Comparative analysis was carried out to ensure the authenticity of the results. The effects of the involved parameters on fluid velocity, temperature, skin friction coefficient, and Nusselt number are presented in graphical and tabular forms with comprehensive discussions in this paper.

Mathematical modeling and heat transfer in nanofluid flow of Newtonian material between two rotating disks

Here, we have discussed the irreversibility in MHD hybrid nanofluid flow with Joule heating, viscous dissipation and activation energy between stretchable rotating disks. Where heat generation, Joule heating and dissipation effects are used to model heat equation while activation energy is used mass equation just to start a chemical reaction. Here, $${\text{GO}}$$ (graphene oxide) and $${\text{TiO}}_{2}$$ (titanium dioxide) with water are used as nanofluids. Contrast of thermophysical properties of these two nanoparticles is very useful because there is huge difference between their thermal conductivities and density. It is very useful to study the velocity, temperature, concentration, entropy generation, Bejan number, skin friction and Nusselt number in contrast of these two nanoparticles. Total entropy rate by thermodynamics second law is computed. Physical features of entropy rate in nanofluids with activation energy are accounted. Nonlinear PDEs are changed to ODEs through transformations. The formulated nonlinear systems are computed through ND-solve method. Influence of several interesting parameters on velocity filed entropy rate, Bejan number, concentration and temperature is graphically discussed for $${\text{TiO}}_{2}$$ and $${\text{GO}}$$ . Velocity and temperature gradients are computed against flow variables. Larger Brinkman number improves the entropy rate. Higher diffusion variables augment both Bejan number and entropy rate.