Effects Of Nanoparticle Volume Fraction Research Articles

Heat transfer across an array of cylinders arranged in inline and staggered formation in a heat exchanger: effect of nanoparticle volume fraction, nanoparticle diameter, and Richardson number

Heat transfer across an array of cylinders arranged in inline and staggered formation in a heat exchanger: effect of nanoparticle volume fraction, nanoparticle diameter, and Richardson number

Enhanced Efficiency of MHD-Driven Double-Diffusive Natural Convection in Ternary Hybrid Nanofluid-Filled Quadrantal Enclosure: A Numerical Study

The study investigates the performance of fluid flow, thermal, and mass transport within a cavity, highlighting its application in various engineering sectors like nuclear reactors and solar collectors. Currently, the focus is on enhancing heat and mass transfer through the use of ternary hybrid nanofluid. Motivated by this, our research delves into the efficiency of double-diffusive natural convective (DDNC) flow, heat, and mass transfer of a ternary hybrid nanosuspension (a mixture of Cu-CuO-Al2O3 in water) in a quadrantal enclosure. The enclosure’s lower wall is set to high temperatures and concentrations (Th and Ch), while the vertical wall is kept at lower levels (Tc and Cc). The curved wall is thermally insulated, with no temperature or concentration gradients. We utilize the finite element method, a distinguished numerical approach, to solve the dimensionless partial differential equations governing the system. Our analysis examines the effects of nanoparticle volume fraction, Rayleigh number, Hartmann number, and Lewis number on flow and thermal patterns, assessed through Nusselt and Sherwood numbers using streamlines, isotherms, isoconcentration, and other appropriate representations. The results show that ternary hybrid nanofluid outperforms both nanofluid and hybrid nanofluid, exhibiting a more substantial enhancement in heat transfer efficiency with increasing volume concentration of nanoparticles.

Investigation of forced convection of a novel hybrid nanofluid containing NEPCM in a square microchannel: Application of single-phase and Eulerian-Eulerian two-phase models

In the present study, laminar forced convection flow and heat transfer of novel hybrid nanofluid of Al 2 O 3 -n-octadecane/water through a horizontal microchannel under a constant wall heat flux condition are investigated. N-octadecane is regarded as a nano-encapsulated phase change material (NEPCM). Simulations are performed utilizing single-phase and Eulerian-Eulerian two-phase models. Governing equations are discretized by finite volume method and then solved using SIMPLE algorithm. Effects of nanoparticles volume fraction ( φ ), Reynolds number ( Re ), and melting range ( T mr ) on thermal and hydrodynamic parameters of hybrid nanofluid are evaluated. It is shown that predictions by Eulerian-Eulerian approach are more accurate than those by single-phase approach when compared to available experimental data. Addition of Al 2 O 3 and n-octadecane nanoparticles to water-based fluid leads to a reduction in fluid and wall temperatures, which is intensified at higher φ and Re . Also, these nanoparticles do not have a significant effect on hydrodynamic development of flow, while they delay its thermal development. NEPCM with a higher T mr only slightly improves thermal performance of hybrid nanofluid, which is more noticeable in single-phase procedure. Total efficiency of hybrid nanofluid ( η hnf ) is amplified by raising φ for both approaches. This augmentation is more evident in Eulerian-Eulerian model due to better thermal and hydrodynamic performances. Maximum increases in η hnf concerning single-phase and Eulerian-Eulerian models are 27% and 60%, respectively, occurring at φ Al 2 O 3 = 1 % and φ n ‐ octadecane = 10 % . Therefore, this type of hybrid nanofluids, because of its enhanced thermo-physical properties, can be considered as a suitable candidate for thermal energy storage, heat transfer, and renewable energy applications.

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.

MHD heat and mass transfer nanofluid flow on a porous cylinder with chemical reaction and viscous dissipation effects: Benchmark solutions

The present study deals with a parametric study of heat and mass transfer of a steady, laminar, and 2D nanofluid flow under the influence of an inclined magnetic field, curvature, permeable medium, thermal radiation, electrical resistance heating, viscous dissipation, heat source/sink, chemical reaction, and concentration power-law exponent effects. Similarity transformations are employed to convert highly nonlinear PDEs to highly nonlinear ODEs. The Frobenius method was used to obtain the heat and mass transfer solutions in terms of hypergeometric function. Iron Oxide Black and water are used as the nanoparticles and base fluid, respectively. Heat and mass transfer boundary conditions are classified as PST (Prescribed surface temperature) and PSC (Prescribed surface concentration), respectively. The effects of nanoparticle volume fraction and curvature parameters on the local skin friction coefficient have been presented. The Box-Behnken design (BBD) is employed to demonstrate the effects of nanoparticle volume fraction parameter, Darcy number, and chemical reaction parameter on the local Sherwood number. Results show that the curvature parameter directly affects the local skin friction coefficient and velocity. In addition, with a rising concentration power-law exponent parameter, the thickness of the concentration boundary layer becomes thinner.

Numerical investigation of mixed convection and entropy production of nanofluid flow in a corrugated channel using a two‐phase mixture model

AbstractThe two‐dimensional mixed convection in a horizontal sinusoidal corrugated channel (CC) is investigated. The two‐phase mixture model (2PMM) is implemented in Ansys Fluent software to simulate the nanofluid (NF) flow. The mathematical formulation of the 2PMM shows the limitation of the single‐phase mixture model linked to the absence of the slip particle‐fluid velocity and, consequently, the parameters that depend on this factor, particularly the diffusion and the drag coefficients. The laminar mixed convection regime is studied, where the NF copper–water is considered under a uniform temperature wall. The simulation results agree with three published works on mixed laminar convection and forced laminar convection in horizontal CC. The effects of nanoparticles volume fraction (ϕ), Richardson number (Ri), wavelength (λ), and wave amplitude (α) are investigated. The results showed that for a mixed flow, the improvement of heat transfer in a horizontal CC could essentially be obtained for a low Ri, where for a given λ, the submits an apparent increase with the increase of λ, that is, for Ri = 0.05 (λ = 3, α = 0.3, ϕ = 3%), the enhancement is 29.7% for and 128.5% for average entropy production compared to the smooth channel. The effect of ϕ on or is weakly dependent on Ri. The use of a Cu–water NF with a volume fraction of 5% (α = 0.2, λ = 2) leads to an increase in the of 17.6% for Ri = 0.05 and 16.4% for Ri = 10 compared to conventional water fluid.

Nanofluid filled enclosures: potential photo-thermal energy conversion and sensible heat storage devices

In the present work we propose “nanofluid filled enclosures” as potential photo-thermal energy conversion and sensible heat storage devices. Herein, the optical charging of the nanofluid has been modeled as “solar radiant energy - nanoparticles” interaction. The subsequent energy redistribution has been modeled as coupled transport phenomena involving mass, momentum and energy transport. In particular, nanofluid filled enclosure with adiabatic, and isothermal (through convective) boundaries have been analyzed to decipher the fundamental limits of sensible heat storage and thermal discharging capacities respectively. Furthermore, the effect of nanoparticles volume fraction on the photo-thermal energy conversion mechanisms and its redistribution thereof has been critically investigated. Detailed analysis reveals that under similar operating conditions, in volumetric absorption mode (i.e., at low nanoparticles volume fraction) nanofluid filled enclosure has higher sensible heat storage (8%–20% higher) and thermal discharging (13%–58% higher) capacities than in the corresponding surface absorption mode (i.e., at high nanoparticles volume fraction). Overall, “nanofluid filled enclosures”, particularly in volumetric absorption mode, could be deployed for efficient solar thermal conversion and storage.

Numerical analysis of MHD nanofluid flow and heat transfer in a circular porous medium containing a Cassini oval under the influence of the Lorentz and buoyancy forces

AbstractThis paper reports our study on the flow characteristics and heat transfer performance of magnetohydrodynamics (MHD) nanofluid in an innovative porous, circle‐shaped enclosure incorporating a Cassini oval cavity using the Darcy law. The MHD nanofluid considered in this study is Al2O3–H2O. A two‐dimensional (2D) mathematical model is developed based on a homogeneous model. The formulation of the vorticity stream function is then used to obtain coupled equations. Finally, the coupled partial differential equations are solved numerically using the finite element method. Model predictions are then compared against results from the previously published study to verify the accuracy and validity of the developed model, and a good agreement is achieved. Figures demonstrate the effects of nanoparticle volume fraction, inclined angle, Lorentz, and buoyancy forces on the MHD nanofluid flow. The results indicate that the convection mechanism becomes weaker with an increase in solid nanoparticle volume fraction. A significant increase in the Rayleigh number will lead to a stronger and more cohesive core vortex. In addition, when magnetic force is applied horizontally, favorable Nuave occurs. Based on the numerical results, a correlation to predict the average Nusselt number within the enclosure is developed as a function of Hartmann number (Ha), Rayleigh number (Ra), and inclined angle (γ).

Thermophysical Properties of Nanofluid in Two-Phase Fluid Flow through a Porous Rectangular Medium for Enhanced Oil Recovery.

It is necessary to sustain energy from an external reservoir or employ advanced technologies to enhance oil recovery. A greater volume of oil may be recovered by employing nanofluid flooding. In this study, we investigated oil extraction in a two-phase incompressible fluid in a two-dimensional rectangular porous homogenous area filled with oil and having no capillary pressure. The governing equations that were derived from Darcy’s law and the mass conservation law were solved using the finite element method. Compared to earlier research, a more efficient numerical model is proposed here. The proposed model allows for the cost-effective study of heating-based inlet fluid in enhanced oil recovery (EOR) and uses the empirical correlations of the nanofluid thermophysical properties on the relative permeability equations of the nanofluid and oil, so it is more accurate than other models to determine the higher recovery factor of one nanoparticle compared to other nanoparticles. Next, the effect of nanoparticle volume fraction on flooding was evaluated. EOR via nanofluid flooding processes and the effect of the intake temperatures (300 and 350 K) were also simulated by comparing three nanoparticles: , , and . The results show that adding nanoparticles (<5 v%) to a base fluid enhanced the oil recovery by more than 20%. Increasing the inlet temperature enhanced the oil recovery due to changes in viscosity and density of oil. Increasing the relative permeability of nanofluid while simultaneously reducing the relative permeability of oil due to the presence of nanoparticles was the primary reason for EOR.

Experimental study on the density, surface tension and electrical properties of ZrO2–EG nanofluids

ABSTRACT The article focuses on the physical properties of nanofluids based on ethylene glycol (EG) with dispersed zirconium dioxide (ZrO2) nanoparticles. For this purpose, the two-step method was applied to prepare samples with five different nanoadditive volume fractions (0.002, 0.004, 0.006, 0.0081, 0.0102). No surfactants were used in the sample preparation process. All materials are commercially available and were used without any modification. To determine the physical properties of ZrO2-EG nanofluids, various techniques were used. Oscillating U-tube method, Du Noüy ring method Ohm law, and dielectric spectroscopy were applied to obtain the mass density, surface tension, electrical conductivity and permittivity, respectively. All measurements were performed at a constant temperature of 298.15 K. The effect of nanoparticles volume fraction on the physical properties of the prepared nanofluids was determined. The mass density, surface tension, electrical conductivity and permittivity increase with the increasing content of ZrO2 in ethylene glycol.

Cooling of a lithium-ion battery using microchannel heatsink with wavy microtubes in the presence of nanofluid

The cooling process is important for the thermal management of lithium-ion batteries, and maintaining their operating temperature in the optimal range is essential because high temperatures, in addition to reducing efficiency, can damage the batteries. In recent years, many studies have been conducted to achieve an efficient thermal management system (TMS) and the effect of coolant flow distribution in mini-channels, but simultaneous utilization of wavy microchannels and microtubes in a cooling system is a new topic that is addressed in the present work. In this study, silver-water/ethylene glycol nanofluid is considered as a biologically synthesized working fluid, and the effect of nanoparticle volume fraction (ϕ), Reynolds number (Re), and inlet and outlet arrangement on thermal performance and battery temperature changes are examined. The results demonstrate that the use of HS in all cases reduces the temperature of the battery surface and the use of nanofluid in this cooling system keeps its temperature within a safe operating range. Also, counter flow in microchannel and microtube creates a more uniform temperature profile on the battery surface, keeping the battery temperature in the range of 300 to 310 K. For parallel flow, the battery temperature is in the range of 303 to 312 K. In all cases, the temperature difference between different points on the battery surface is less than 5°. Besides, an increment in Re and ϕ enhances the entropy generation of the system.

The effects of water-CuO nanofluid flow on heat transfer inside a heated 2D channel

The velocity distribution and heat transfer improvement in a two-dimensional channel filled with a water-CuO nanofluid is numerically studied. The nanofluid flow is assumed laminar and one-phase with Newtonian behaviour. Pure water is considered as the base fluid, and water-CuO nanofluid with four different volume fractions of CuO nanoparticles are examined. A constant heat source–sink is considered to cover the entire length of the bottom wall of the channel while the upper wall is assumed thermally insulated. The control volume technique is used to discretize the governing differential equations, and the SIMPLE algorithm is used to solve the velocity-pressure coupling. A CFD simulation is applied on nanofluid flow utilizing ANSYS FLUENT to solve the governing equations of the flow. The effects of nanoparticle volume fraction on the heat transfer, velocity profile, wall shear stress, skin friction coefficient, and Nusselt number along the channel have also been examined. The results confirm that the volume fraction of nanoparticles plays an important role in heat transfer enhancement and hydrodynamic behaviour of flow. The results are presented in figures and tables.

Numerical analysis of convective heat transfer on straight finned tube with different nano fluids

The major idea of this effort is to study and analyse heat transfer through a straight finned duct with different nanofluids. Dynamics and simulations for fluid flow at the start of fully developed laminar flow with nanofluids in a circular duct with and without fins under constant wall temperature conditions are performed by using fluent commercial software. Heat transfer behaviours of the duct are investigated for constant wall temperature conditions for oxides of nanofluid. The thermal properties of nanofluid are considered from the literature. Commercial software ANSYS 2018 was used to compute the velocity and thermal analysis between the inlet and outlet of the tube. The finite volume method will be used to discretize the whole domain in quadratic elements considered with the turbulence model. Turbulence differential equations system coupled with the heat convection. The flow and pressure, the temperature in the exit will be calculated as a function of initial conditions in the entrance of the duct. The fluid properties such as conductivity and viscosity of the base fluid are taken as temperature independent. The enhancement in heat transfer rate are presented graphically with the effect of effects of nanoparticle volume fraction, nanoparticle size.

Unsteady Boundary Layer Flow Over a Permeable Stretching/Shrinking Cylinder Immersed in Nanofluid

In this study, the unsteady boundary layer flow over a stretching/shrinking cylinder immersed in nanofluid with the presence of suction effect is analyzed. The governing partial differential equations are converted to ordinary differential equations by introducing similarity transformation variables. The shooting method is applied to solve the system where the numerical solutions are obtained and presented graphically. The study's objective is to investigate the effect of nanoparticle volume fraction, the unsteadiness parameter, the stretching/shrinking parameter on the velocity and temperature gradients. It is found that the dual solutions are obtained in a specific range of these parameters for both stretching and shrinking cylinders. Besides, a high volume of the nanoparticle in the base fluid increases the velocity gradient and decreases the temperature gradient at the surface. Also, increasing nanoparticle volume fraction in the base fluid expands the solution's range, which denotes the boundary layer separation from the surface has been delayed. The existence of dual solutions allows stability analysis performance by introducing a new dimensionless variable and is solved using bvp4c function in Matlab software. This phase obtains the smallest eigenvalue, showing that the first solution is stable and physically realizable while the second solution is not stable.

Parametric investigation of a nanofluid-NEPCM based spectral splitting photovoltaic/thermal system

Photovoltaic cells can convert incoming sunlight within their responsive wavelength range into electricity. Unfortunately, the majority of the incident radiation is reflected, absorbed directly as heat, or indirectly converted to heat due to internal losses (i.e., ≥ 52.9%, even world-record efficiency cells). In concentrated photovoltaic systems, this added heat can further degrade the electrical conversion efficiency of the cells if it is not removed, resulting from an elevated operating temperature. Spectral splitters and absorptive filters can remove the unused portion of the solar spectrum before it is converted to heat in the photovoltaic cells and harvest this energy for active use in thermal applications. In this paper, an innovative concentrated photovoltaic/thermal system that utilizes a layered design containing an optical fluid and a phase change material was investigated as a new alternative absorptive filter. Five possible configurations of this filter were compared from energy, exergy, and energy storage perspectives. These layers consist of a phase change material (dotriacontane, a paraffin) layer and fluid channel layers (a glycerol fluid) with suspended Ag and/or Au nanoparticles. The optical properties of the nanofluid and the nano-enhanced phase change material (NEPCM) were modeled using Mie and Rayleigh scattering theories. The comparison showed that the configuration containing the nanofluid channel at the top of the nano-enhanced phase change material performs well in all aspects of energy, exergy, and energy storage. A parametric study was conducted to determine the effects of nanoparticles volume fraction, concentration ratio, mass flow rate, nanofluid thickness and phase change material thickness on PV/T system performance with this filter configuration. It was found that volume fractions lower than 0.3 × 10−5 and 0.2 × 10−5 for Ag and Au, respectively, provided the best system performance for the assumed geometric and operational conditions. At an optimal mass flow of 0.005 kg s−1 for the nanofluid, this design achieved a maximum exergetic efficiency of 24% for a concentration ratio of 30. The results also revealed that the nanofluid-NEPCM filter is not suitable for concentration ratios of less than 10. Overall, this study finds that nanofluid-NEPCM-based spectral splitter, in addition to successfully filtering radiation, can store energy efficiently.

Entropy generation of three-dimensional Bödewadt flow of water and hexanol base fluid suspended by $$\hbox {Fe}_{{{3}}}\hbox {O}_{{{4}}}$$ and $$\hbox {MoS}_{{{2}}}$$ hybrid nanoparticles

In this study, three-dimensional Bodewadt hybrid nanofluid flow has been investigated. Base fluids are water and hexanol which contain $$\hbox {Fe}_{3}\hbox {O}_{4}$$ and $$\hbox {MoS}_{2}$$ . The governing nonlinear PDEs are converted into nonlinear ODEs and the nonlinear equations are solved by the homotopy perturbation method (HPM). The effects of nanoparticle volume fraction, Eckert number, base fluid and shape factor on entropy generation, Nusselt number, skin friction coefficient and Bejan number have been studied. Entropy generation is increased with an increment in Eckert number; while, it is decreased by growth in nanoparticle volume fraction and shape factor. In a similar situation, hexanol has higher rate of irreversibility, higher Bejan number and higher Nusselt number than water. The skin friction coefficient is not a function of the Eckert number and shape factor, but it is an increasing function of nanoparticle volume fraction. In this paper, by averaging the differences of Nusselt number and skin friction coefficient between water and hexanol, it can be observed that the Nusselt number and skin friction coefficient for hexanol are 11% and 5% more than water, respectively. Indeed, in a fixed situation, hexanol-based fluid flows have higher heat transfer and drag than water-based fluid flows.

Experimental studies on elastic properties of high density polyethylene-multi walled carbon nanotube nanocomposites

The effect of nanoparticle volume fraction on the elastic properties of a polymer-based nanocomposite was experimentally investigated and the obtained results were compared with various existing theoretical models. The nanocomposite was consisted of high density polyethylene (HDPE) as polymeric matrix and 0, 0.5, 1 and 1.5 wt.% multi walled carbon nanotubes (MWCNTs) prepared using twin screw extruder and injection molding technique. Nanocomposite samples were molded in injection apparatus according to ASTM-D638 standard. Therefore, in addition to morphological investigations of the samples, tensile tests at ambient temperature were performed on each sample and stress-strain plots, elastic moduli, Poisson's ratios, and strain energies of volume units were extracted from primary strain test results. Tensile test results demonstrated that 1 wt.% nanoparticles presented the best reinforcement behavior in HDPE-MWCNT nanocomposites. Due to the agglomeration of nanoparticles at above 1 wt.%, Young' s modulus, yielding stress, fracture stress, and fracture energy were decreased and Poisson's ratio and failure strain were increased.

Thermal Analysis of Flat Plate Solar Collector Using Different Nanofluids and Nanoparticles Percentages

Flat plate solar collector (FPSC) is commonly used due to its low price, less complexity, and easier installation and operation. The low thermal efficiency is the main disadvantage of this type of solar collectors. In the present study, the thermal performance of the FPSC using alumina oxide -water and copper oxide -water nanofluids are evaluated. The effect of nanoparticle volume fraction and nanoparticle type are investigated theoretically and validated experimentally. A computational fluid dynamic model is developed. The model is validated with experimental result carried in this study. The model is simulated under the hot climate conditions of Egypt. The results showed that the presence of the nanoparticles in the working fluid of the FPSC increases the pressure drop in the collector, but thermal performance enhancement is also obtained. Further, an optimum nanoparticles volume fraction of 0.5% of copper oxide nanoparticle is found to attain the highest thermal efficiency of the collector. Furthermore, using copper oxide-water nanofluid is effective than using alumina oxide-water nanofluid at the same conditions.

Numerical analysis of forced convection heat transfer in a rectangular micro-channel totally filled with Ag/ water nano fluid in slip flow regime using the lattice Boltzmann method

Numerical simulation reported on heat transfer and fluid flow in a two-dimensional rectangular micro channel totally filled with Ag/water. The first –order slip/jump boundary conditions were uniformly imposed to the up and bottom walls. The governing conservation equations are translated in dimensionless form using the thermal Single Relaxation Time (T-SRT) modified Lattice Boltzmann Method (LBM) with double distribution functions (DDFs). The viscous dissipations effects are adopted into the energy equation. Effects of nanoparticle volume fraction φ, slip coefficient, B, on the flow of Nano fluid and heat transfer were studied. The results were interpreter in terms of slip velocity; temperature jump and Nusselt number. Based on the results found, it can be concluded that decreasing the values of slip coefficient enhances the convective heat transfer coefficient and consequently the Nusselt number (Nu) but increases the slip velocity at the wall and temperature jump values.

Improving the Performance of A Flat Plate Solar Collector Using Nanofluid as Working Fluid

Solar energy is the best alternative to limited fossil fuels. The foremost important means of utilizing solar energy are solar collectors. The most common types of solar collectors are flat plate solar collectors. A great deal of theoretical research has been conducted to enhance the flat plate solar collector efficiency. One effective way to increase the efficiency is by using an improved thermal properties fluid as nanofluid. In this paper, a numerical study has been made to enhance the efficiency and improve the performance of solar collector via the use of (Multi-Wall Carbon Nano Tube-water) MWCNT-H2O nanofluid instead of traditional fluid like water as working fluid under the weather of Mosul city / Iraq (36.3489° N, 43.1577° E). One dimensional dynamic model using implicit finite difference method was used. Solving energy conservation equations through the various layers of the solar system is the basis upon which the current model was based. Effects of nanoparticle volume fraction and mass flow rate on the working fluid stream temperature differences, and the thermal efficiency were studied. The mass flow rate was varied from 0.004 kg/s to 0.03 kg/s, while the volume fraction was varied from 0% to 6%. The results of "Nanofluid Based Flat Plate Solar Collector" were compared with the experimental results presented by [1]. The comparison established a good match between the current results and experimental results. The results showed an increase in the working fluid outlet and inlet temperature difference and collector thermal efficiency due to the addition of MWCNT nanoparticles. The temperature difference of "Nanofluid Based Flat Plate Solar Collector" was found 28.8⁰C at 0.014 kg/s and 6% in April, while it was 25 ⁰C at the same condition in the "Water Based Flat Plate Solar Collector case". Also, the thermal efficiency of "Nanofluid Based Flat Plate Solar Collector" was found 2.41% to 6.68% more than the "Water Based Flat Plate Solar Collector case".