Natural Convection Of Nanofluid Research Articles

Mathematical Modeling of Pseudoplastic Nanofluid Natural Convection in a Cavity with a Heat-Generating Unit and Solid Finned Heat Sink

The power-law nanofluid natural convection in a chamber with a thermally generating unit and a solid ribbed structure has been studied in this work. A mixture of carboxymethylcellulose with water and copper nanoparticles is a working fluid illustrating pseudoplastic properties. The effective properties of the nanoliquid have been described by experimental correlations reflecting the temperature effect. The governing equations have been formulated on the basis of the conservation laws of mass, momentum and energy employing non-primitive parameters such as stream function and vorticity. The defined boundary value problem has been worked out by the finite difference technique using an independently developed calculation system. The Rayleigh number is fixed for analysis (Ra = 105). The paper analyzes the influence of the nanoparticles volume fraction, an increase in which reduces the temperature in the case of the one edge presence. An analysis of the rib height has shown that its growth leads to a weakening of the convective heat transfer, but at the same time, the source temperature also decreases. Increasing the number of fins from 1 to 3 also helps to reduce the average temperature of the heat-generated element by 15%.

Numerical assessment of meshless method for studying nanofluid natural convection in a corrugated wall square cavity

This study aims to investigate the impact of various factors, such as wall shape, Rayleigh number, and volume fraction of nanoparticles, on natural convection in a square cavity that is filled with a mixture of Al2O3 solid particles and liquid water. The research employs numerical simulations based on the radial basis function meshless method and the artificial compressibility technique. The results of the study showed that the temperature distribution in the cavity was mostly uniform, except in the vicinity of the hot wall, while the flow was primarily dominated by convection as the Rayleigh number increased. Furthermore, the heat transfer rate increased with the volume fraction of nanoparticles, indicating the significance of nanoparticles in improving the thermal performance of the system. Additionally, the study found that the average Nusselt number, which characterizes the heat transfer efficiency, was highest when the cavity had a wavy wall. For single and double wavy walls, there were respective enhancements of 32% and 6% compared to a regular wall. Additionally, the Nusselt number increased as the volume fraction of nanoparticles, indicating a significant influence of nanoparticle concentration and wall geometry on the fluid flow and heat transfer characteristics in the square cavity. Consequently, this study's outcomes provide crucial insights into designing and optimizing thermal management systems, particularly those utilizing nanofluids.

A Comprehensive Numerical Analysis of Natural Convection in Nanofluids within Various Enclosure Geometries: A Review

A Comprehensive Numerical Analysis of Natural Convection in Nanofluids within Various Enclosure Geometries: A Review

Numerical Solution of Natural Convection Nanofluid Flow over aNon-Isothermal Vertical Plate

The natural convection nanofluidflow over a non-isothermal vertical plate is studied numerically. The effects of Brownian motion and thermophoresis parameters are incorporated into models used for nanofluids. The non-linear partial differential equations and boundary conditions are transformed into a set of nonlinear ordinally differential equations using the similarity transformations. The resulting system of equations are solved numerically by using shooting techniques. This solution depends on the Prandtl number (Pr), Buoyancy ratio (Nr), Brownian-motion (Nb), thermophoresis parameter (Nt), Lewis number (Le), and power-law exponent (λ). For different values of λ, Le and Pr, the influence of reduced Nusselt number with Nr, Nb and Nt is represented by correlation formulas and compared with previously published results and found to be in better agreement.

A Radiative Chemical Process for the Methylene Blue Degradation by Natural Convective Nanofluid Flow over an Upright Cone.

An upstraight cone with nonisothermal surface velocity, temperature, and concentration was investigated using a numerical solution approach to simulate MHD, MB dye, and various nanofluid flows. Numerical evaluation of the flow field equation was carried out using an excellent finite difference method after it has been converted into a dimensionless form. Different heat transfer occurrences were observed depending on temperature, velocity, and concentration when using several types of nanofluids (TiO, Ag, Cu, and Al2O3Z3). The amount of MB dye that was degraded by the synthesized nanofluids under the influence of sunlight irradiation was 81.40 percent as a catalyst (carbon nanodots). The parametric analysis of various features of flow fields has been shown using graphs. It was observed that heat is generated from the cone during the sun light irradiation reaction, heat is transferred to MB dye containing nanofluids, and heat interacts with nanofluids and is involved in the chemical reaction with the assistance of electrons. As MB dye degrades in the absence of catalysts (carbon nanodots), it is only 52 percent effective. MB dye is degraded at 81.40 percent, then becomes stable, and takes 120 minutes to degrade in nanofluids containing MB dye with catalysts (carbon nanodots).

Numerical and machine learning approaches in nanofluid natural convection flow in a wavy cavity

In this study, machine learning modeling for the average Nusselt number obtained by the numerical simulation of natural convection flow of copper (Cu)-water nanofluid in a wavy cavity is investigated. Radial basis function based finite difference method (RBF-FD) is applied for numerical computations of the dimensionless governing equations of the considered problem. Machine learning techniques, multivariate adaptive regression splines (Mars) and Trilayer Neural Networks (TNN), are used for modeling. The trained data to be used in modeling is built from the results of the numerical calculations. In this data, the output is the average Nusselt number and the inputs are the chosen problem parameters. The test data is also created separately, and the models are tested comparing the results with the corresponding numerical results. TNN predictions are obtained better than Mars predictions on this test data. Instead of re-performing numerical executions to get average Nusselt number at some problem parameter settings, TNN modeling is a good alternative for getting the expected result immediately. The other problem unknowns, stream function and temperature, are also modeled depending only on the coordinates inside the domain in a fixed parameter setting. This results in independence from a numerical method in larger grid distribution.

Entropy optimization of non-Newtonian nanofluid natural convection in an inclined U-shaped domain with a hot tree-like baffle inside and considering exothermic reaction

BackgroundNon-Newtonian fluids with properties differing from those of Newtonian fluids have been concerned due to their wide range of applications in industry and engineering. Natural convection may play a crucial role in numerous industrial manufacturing processes. In addition, TiO2-water nanofluid exhibits better performance owing to their high thermal conductivity, low cost, and dielectric properties. Further, baffles can be utilized to ameliorate heat transfer in the system concern. The second law inspection may be substantial so as to examine the entropy optimization's role in diverse thermic systems. AimWith regard to such advantages, the present article dissects natural convection and entropy production of non-Newtonian TiO2-water nanofluid inside an inclined U-shaped domain subject to a hot tree-like baffle at bottom wall and exothermic reaction. MethodThe FEM is instrumental for obtaining apposite solution of the non-dimensional governing equations. NoveltyPower-law (Ostwald-de Waele) nanofluid flow subject to hot tree-like baffle and Arrhenius kinetics in an inclined U-shaped domain is regarded as a novelty of the present investigation. FindingsEnhancing Frank-Kamenetski number amplifies streamlines (6.25%), horizontal velocity (5.086%), and vertical velocity (6.73%). Augmented Rayleigh number emaciates Bejan number by 75% while that of cavity angle from 450to 900 amplify significantly by 494.14%.

Control of hybrid nanofluid natural convection with entropy generation: A LBM analysis based on the irreversibility of thermodynamic laws

This article analyzes the irreversibility of the natural convection of water/copper nanofluids in a square enclosure. Thermal entropy generation, frictional entropy generation, and total entropy generation are examined by changing the Hartmann number, thickness and length of baffles, and magnetic field with inclinations angle. Three baffles are mounted on the hot wall of the enclosure. The wall in front of the hot wall is cold and the other walls are insulated. The numerical method is employed for this analysis using the Lattice Boltzmann method. The results of this study demonstrate that an increment in the Ha reduces the horizontal and vertical velocity components ​​of the water/copper nanofluids in the enclosure and reduces the temperature gradient. Also, an enhancement in the Ha reduces all types of ETG. An increment in the angle of the magnetic field enhances thermal entropy generation, frictional entropy generation, and total entropy generation. Enhancing the magnetic field, first decreases and then increases the Bejan number.

Corrigendum to “Natural convection of nanofluids in a wavy porous cavity”

In the paper mentioned above, we pointed out some errors in the Nusselt number [Formula: see text] calculation. Through this corrigendum, we are presenting a meaningful discussion of the calculated [Formula: see text] values. It is believed that the readers of Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, will gain better insight into the problem.

Investigation of Nanofluid Natural Convection Inside a Square Cavity for Two Orientations Using Lattice Boltzmann Method

In this study, natural convection heat transfer of a water based nanofluid inside a square cavity is numerically investigated for two different orientations of a wall-heated cavity. The enclosure is heated by applying a constant heat flux while cooled at ambient conditions. Lattice Boltzmann method (LBM) is used to simulate nanofluid natural convection. The Brownian motion of nanoparticles is considered. LBM simulation is validated by comparison with experimental and numerical results of the literature. The effect of Rayleigh number (Ra = 103, 104, 105, 106), Biot number (Bi = 0.1, 1, 10, 100) and volume fraction of nanoparticles (Φ = 0, 1, 3 and 5%) on the isotherms, streamlines, velocity components, local and Nusselt number is analyzed for two oriented cavities. The bottom-heated cavity shows higher heat transfer rate than that of the cavity heated from the sidewall. The average Nusselt number increases by up to 6.81%. Furthermore, Biot number, Rayleigh number, and volume fraction of nanoparticles show significant effects on the heat transfer rate.

Natural Convection of Nanofluids in Partially Filled Metal Foam Sinusoidal Cavities

Natural Convection of Nanofluids in Partially Filled Metal Foam Sinusoidal Cavities

Thermal case study of nanofluid flow in partially heated rectangular enclosure rooted with sinusoidal heated rods and inclined magnetic field

The natural convection nanofluid flow in a partially heated rectangular enclosure is studied numerically. For better novelty, an inclined magnetic field is carried externally. The wavy heated rods are installed at both the bottom and upper walls of an enclosure. Copper-Oxide (CuO) nanoparticles are suspended in the flow field. The nanofluid flow is mathematically formulated in terms of differential equations. The finite element method is used to examine the flow field in a partially heated rectangular enclosure. The flow-affecting parameters are Hartmann number and angle of inclination. The quantity of interest includes horizontal velocity, vertical velocity, and Nusselt number. The outcomes are shared in terms of contour and line plots. It is observed that for increasing values of the Hartmann number, the Nusselt number at the upper heated sinusoidal rod shows a higher magnitude in comparison with a lower heated corrugated rod.

A design of neuro-computational approach for double‐diffusive natural convection nanofluid flow

The artificial intelligence based neural networking with Back Propagated Levenberg-Marquardt method (NN-BPLMM) is developed to explore the modeling of double‐diffusive free convection nanofluid flow considering suction/injection, Brownian motion and thermophoresis effects past an inclined permeable sheet implanted in a porous medium. By applying suitable transformations, the PDEs presenting the proposed problem are transformed into ordinary ones. A reference dataset of NN-BPLMM is fabricated for multiple influential variants of the model representing scenarios by applying Lobatto III-A numerical technique. The reference data is trained through testing, training and validation operations to optimize and compare the approximated solution with desired (standard) results. The reliability, steadiness, capability and robustness of NN-BPLMM is authenticated through MSE based fitness curves, error through histograms, regression illustrations and absolute errors. The investigations suggest that the temperature enhances with the upsurge in thermophoresis impact during suction and decays for injection, whereas increasing Brownian effect decreases the temperature in the presence of wall suction and reverse behavior is seen for injection. The best measures of performance in form of mean square errors are attained as 7.1058×10−10,2.9262×10−10,1.1652×10−08,1.5657×10−10 and 5.5652×10−10 against 969, 824, 467, 277 and 650 iterations. The comparative study signifies the authenticity of proposed solver with the absolute errors about 10−7 to 10−3 for all influential parameters results.

Nanoparticles impacts on natural convection nanofluid flow and heat transfer inside a square cavity with fixed a circular obstacle

Many significant applications may be acquired in specific nanoparticle shapes as well as size range or size. The shape of nano-sized particles is significant in every field of trace metal detection, for biomolecular assays, molecular labeling and the application of nanotechnology. The nanoparticle's shape effects are very noteworthy on the thermal conductivity of suspension. The main focus of the current study is to elaborate the nanoparticles shape impacts on nanofluid flow in a lid-driven square cavity with a fixed circular obstacle at the center. The top wall of the square cavity is adiabatic and moving. The circular cavity and bottom wall of the cavity is heated, while the remaining walls of the cavity are cold. The diamond-water nanofluid contained three kinds of nanoparticles shape namely Sphere, Column (nonspherical) and Lamina (nonspherical). The flow-modeled phenomena is governed in form of coupled partial differential equations and is tackled with finite element method (FEM). The flow distribution analysis is deliberated in form of streamlines, isothermal contour patterns, velocity distribution, temperature distribution, kinetic energy and Nusselt number. The graphical results indicate that the Lamina (nonspherical) shape nanoparticles have higher performance in (diamond-water) temperature distribution and heat transfer.

Enhancement of natural convection of a nanofluid by stress-free patches in an L-shaped enclosure

Purpose This study aims at investigating the heat transfer characteristics of a nonsquare enclosure when hydrodynamic resistance is altered discontinuously along its inner surface. Particularly, it focuses on investigating how several essential factors collaboratively influence the natural convection, including the Rayleigh number (Ra), the aspect ratio (AR), the nanoparticle volume fraction (ϕ) and the locations of changing hydrodynamic resistance. Design/methodology/approach To achieve these objectives, an L-shaped enclosure of various AR is adopted, while zero local shear resistance is applied and modeled by stress-free (SF) patches of four distinct arrangements (corresponding to Cases 1–4). The nanofluid is modeled by Buongiorno’s two-phase model. The effects are explored using an in-house numerical framework based on a hybrid lattice Boltzmann-finite difference method with the total variation minimization scheme. Findings The results show that when Ra is sufficiently large, i.e. Ra = 105, SF patches can generally enhance the heat transfer performance regardless of other factors. However, the ways of achieving those enhancements are different, which mainly depend on the arrangement of the SF patches and AR but are nearly independent of ϕ. The maximum improvement of heat transfer can be achieved in Case 3 with AR = 0.6, Ra = 105 and ϕ = 0.04, where the averaged Nusselt number is enhanced by 8.89%. Originality/value This study presents a new scenario where the SF patches of various arrangements are applied to enhance the nanofluid natural convection of a nonsquared enclosure, and it reveals how the improvement is achieved and cooperatively affected by several important factors.

Experimental investigation of natural convection of Fe3O4-water nanofluid in a cubic cavity

Convective heat transfer of nanofluids has been an active research topic in recent times. But the relative amount of research in natural convection of nanofluids is scarce in comparison with forced convection. In this study the effect of Fe3O4/water nanofluid on the natural convection behavior in a differentially heated cubic cavity of characteristic length 30 mm has been investigated. The nanofluids are synthesized using a two-step approach and their thermophysical properties like thermal conductivity and viscosity are measured in the temperature ranging from 20 to 60 ° C . The effect of nanoparticle volume fraction on heat transfer performance is studied with concentration ranging from 0–0.8% by volume. The cavity is made up of Poly-lactic acid (PLA) with two sides covered with copper plates. One of the copper plates is kept in contact with ambient atmosphere while variable heat flux using silica gel heater is applied on the other copper plate. All previous results have shown either monotonous deterioration or an increment followed by a continuous decrease in heat transfer coefficient and Nusselt number with increase in concentration. The results of this study have shown that for constant input heat flux the Nusselt number decreases monotonously. Further it is observed that for constant Rayleigh number there is an increase in Nusselt number with increase in concentration.

Hybrid nanofluid natural convection in the square enclosure with periodic magnetic field: experimental investigation and economic evaluation

Hybrid nanofluid natural convection in the square enclosure with periodic magnetic field: experimental investigation and economic evaluation

Numerical Assessment of Nanofluid Natural Convection Using Local RBF Method Coupled with an Artificial Compressibility Model

In this paper, natural heat convection inside square and equilateral triangular cavities was studied using a meshless method based on collocation local radial basis function (RBF). The nanofluids used were Cu-water or -water mixture with nanoparticle volume fractions range of . A system of continuity, momentum, and energy partial differential equations was used in modeling the flow and temperature behavior of the fluids. Partial derivatives in the governing equations were approximated using the RBF method. The artificial compressibility model was implemented to overcome the pressure velocity coupling problem that occurs in such equations. The main goal of this work was to present a simple and efficient method to deal with complex geometries for a variety of problem conditions. To assess the accuracy of the proposed method, several test cases of natural convection in square and triangular cavities were selected. For Rayleigh numbers ranging from to , a validation test of natural convection of Cu-water in a square cavity was used. The numerical investigation was then extended to Rayleigh number , as well as -water nanofluid with a volume fraction range of . In a second investigation, the same nanofluids were used in a triangular cavity with varying volume fractions to test the proposed meshless approach on non-rectangular geometries. The numerical results appear to be in agreement with those from earlier investigations. Furthermore, the suggested meshless method was found to be stable and accurate, demonstrating that it may be a viable alternative for solving natural heat transfer equations of nanofluids in enclosures with irregular geometries.

Casson Hybrid Nanofluid Natural Convection in Trapezoidal Cavity containing a Partially Heated Wall

A computational analysis has been performed for Casson hybrid nanofluid natural convection heat transfer in trapezoidal cavity containing a partially heated at bottom wall, and the incline walls are set to be at the cold temperature while the top wall is supposed to be adiabatic. The hybrid nanoparticles, alumina and copper are dispersed in ethylene glycol and water mixture has been used as a working fluid. The finite element method is used to solve the nondimensional governing partial differentials equations. The numerical results are carried out for different governing parameters such as Casson parameter Rayleigh number and hybrid nanoparticles volume fraction and heated zone length. The influence of these parameters on streamlines, isotherms, velocities and average Nusselt number will be the focus in this study.

Multi-Phase Nano Fluid Natural Convection in A Partially Divided Cavity for Cooling of Radioactive Waste Containers

The innovation of this investigation is fins arrangement effects on Al2O3-water Nano fluid natural convection in a partially divided cavity for energy storage systems and cooling of radioactive waste containers. Simulation of fluid velocity and temperature fields done based on the Lattice Boltzmann Model using the D2Q9 and D2Q5 methods, respectively. Streamline, isotherm, Nusselt number, velocity and temperature fields have been studied for different shapes of fins. In this investigation, we surveyed 4 shape of fins that arranged in three cases; case 1: yL=0.25 L, yR=0.75 L, case 2: yL=0.5 L, yR=0.5 L and Case 3: yL=0.75 L, yR=0.25 L. The results illustrated, assuming case 2: yL=0.5 L, yR=0.5 L is base case, so with changing arrangement of fins for case 1: yL=0.25 L, yR=0.75 L, rate percentage of average Nusselt number for cavities arranged with rectangular, circle, vertical and horizontal Ellipse fins were %26, %8, %4 and %8, respectively. Furthermore, with changing arrangement of fins to case 3: yL=0.75 L, yR=0.25 L, these percentages were %62, %24, %14 and %22.