Momentum and heat transfer characteristics of three-dimensional CuO/water nanofluid flow in a horizontal annulus: influences of nanoparticle volume fraction and its mean diameter

Flow And Heat Transfer ◽

Heat Transfer Capacity

The study of the influence of the nanoparticle volume fraction and aspect ratio of microchannels on the fluid flow and heat transfer characteristics of nanofluids in microchannels is important in the optimal design of heat dissipation systems with high heat flux. In this work, the computational fluid dynamics method was adopted to simulate the flow and heat transfer characteristics of two types of water–Al2O3 nanofluids with two different volume fractions and five types of microchannel heat sinks with different aspect ratios. Results showed that increasing the nanoparticle volume fraction reduced the average temperature of the liquid–solid heat transfer surface and thereby improved the heat transfer capacity of the nanofluids. Meanwhile, the increase of the nanoparticle volume fraction led to a considerable increase in the pumping power of the system. Changing the aspect ratio of the microchannel effectively improved the heat transfer capacity of the heat sink. Moreover, increasing the aspect ratio effectively reduced the average temperature of the heating surface of the heat sink without significantly increasing the flow resistance loss. When the aspect ratio exceeded 30, the heat transfer coefficient did not increase with the increase of the aspect ratio. The results of this work may offer guiding significance for the optimal design of high heat flux microchannel heat sinks.

A numerical investigation on the heat transfer characteristics of nanofluid flow in a three-dimensional microchannel with harmonic rotating vortex generators

Journal of Thermal Analysis and Calorimetry ◽

10.1007/s10973-019-08402-6 ◽

2019 ◽

Vol 139 (1) ◽

pp. 755-764 ◽

Cited By ~ 8

Author(s):

Y. Amini ◽

S. Akhavan ◽

E. Izadpanah

Keyword(s):

Heat Transfer ◽

Numerical Investigation ◽

Three Dimensional ◽

Vortex Generators ◽

Nanofluid Flow ◽

Transfer Characteristics

Numerical Study on the Fluid Flow and Heat Transfer Characteristics of Al2O3-Water Nanofluids in Microchannels of Different Aspect Ratio

Micromachines ◽

10.3390/mi12080868 ◽

2021 ◽

Vol 12 (8) ◽

pp. 868

Author(s):

Huajie Wu ◽

Shanwen Zhang

Keyword(s):

Heat Transfer ◽

Aspect Ratio ◽

Volume Fraction ◽

High Heat ◽

High Heat Flux ◽

Nanoparticle Volume Fraction ◽

Flow And Heat Transfer ◽

Heat Transfer Capacity

The study of the influence of the nanoparticle volume fraction and aspect ratio of microchannels on the fluid flow and heat transfer characteristics of nanofluids in microchannels is important in the optimal design of heat dissipation systems with high heat flux. In this work, the computational fluid dynamics method was adopted to simulate the flow and heat transfer characteristics of two types of water-Al2O3 nanofluids with two different volume fractions and five types of microchannel heat sinks with different aspect ratios. Results showed that increasing the nanoparticle volume fraction reduced the average temperature of the heat transfer interface and thereby improved the heat transfer capacity of the nanofluids. Meanwhile, the increase of the nanoparticle volume fraction led to a considerable increase in the pumping power of the system. Increasing the aspect ratio of the microchannel effectively improved the heat transfer capacity of the heat sink. Moreover, increasing the aspect ratio effectively reduced the average temperature of the heating surface of the heat sink without significantly increasing the flow resistance loss. When the aspect ratio exceeded 30, the heat transfer coefficient did not increase with the increase of the aspect ratio. The results of this work may offer guiding significance for the optimal design of high heat flux microchannel heat sinks.

The effect of volume fraction of SiO2 nanoparticle on flow and heat transfer characteristics in a duct with corrugated backward-facing step

Thermal Science ◽

10.2298/tsci18s5435e ◽

2018 ◽

Vol 22 (Suppl. 5) ◽

pp. 1435-1447 ◽

Cited By ~ 2

Author(s):

Recep Ekiciler ◽

Emre Aydeniz ◽

Kamil Arslan

Keyword(s):

Heat Transfer ◽

Volume Fraction ◽

Numerical Study ◽

Expansion Ratio ◽

Uniform Heat Flux ◽

Backward Facing Step ◽

Nanofluid Flow ◽

Flow And Heat Transfer

In this paper, flow and heat transfer characteristics of SiO2-water nanofluid flow over a corrugated backward-facing step are numerically investigated. The numerical study is performed by solving governing equations (continuity, momentum, and energy) with finite volume method. The duct inlet and step heights are 4.8 mm. The expansion ratio is 2. The upstream wall, Lu, and downstream wall, Ld, lengths are 48 cm and 96 cm, respectively. The downstream wall of the duct is subjected to a constant and uniform heat flux of 2000 W/m2. The ranges of the volume fraction of nanoparticles and Reynolds number are 0%-3.0% and 135-240, respectively. The effects of the volume fraction of nanoparticles on the average Nusselt number, average Darcy friction factor, and velocity distribution are investigated under laminar forced convective nanofluid flow condition. It is revealed that the nanoparticle volume fraction substantially influences the heat transfer and flow characteristics. The volume fraction of 3.0% shows the highest heat transfer performance.

Numerical Simulation of Al2O3-Water Nanofluid Flow and Heat Transfer in a Tube with Angled Rings

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.931-932.1168 ◽

2014 ◽

Vol 931-932 ◽

pp. 1168-1172 ◽

Cited By ~ 2

Author(s):

Pongjet Promvonge ◽

Somchai Sripattanapipat ◽

Withada Jedsadaratanachai

Keyword(s):

Heat Transfer ◽

Volume Fraction ◽

Three Dimensional ◽

Simple Algorithm ◽

Vortex Pair ◽

Flow And Heat Transfer ◽

Spacing Ratio ◽

Drastic Increase

A numerical investigation has been conducted to examine turbulent flow and heat transfer characteristics in a three-dimensional isothermal tube mounted with 60° angled rings (AR). The ARs with pitch spacing ratio, PR=1.0 and various blockage ratios (BR) ranging from 0.025-0.1 are introduced. The computations are based on a finite volume method and the SIMPLE algorithm has been implemented. The fluid flow and heat transfer characteristics are presented for Reynolds number (Re) ranging from 3000 to 12000. To generate a main counter-vortex pair flow in the tube, ARs at an attack angle of 60° are mounted repeatedly in the tube. Effect of different BRs at a single PR and nanofluid, Al2O3water, with volume fractions 1% and 5% on heat transfer and friction loss is investigated. It is apparent that two main vortex flows created by the ARs exist and help to induce impinging flows on the tube wall leading to drastic increase in heat transfer rate over the tube. The increment in the BR gives rise to the increase in the Nusselt number and friction factor. The computational results reveal that the maximum thermal enhancement factor for the AR with BR=0.025 is found to be 1.8 at Re =3000. The results show that nanofluid, Al2O3 water, can increase the thermal performance when increasing volume fraction to 5%.

Conduction and convection heat transfer characteristics of water-based au nanofluids in a square cavity with differentially heated side walls subjected to constant temperatures

Thermal Science ◽

10.2298/tsci130604082t ◽

2014 ◽

Vol 18 (suppl.1) ◽

pp. 189-200 ◽

Cited By ~ 4

Author(s):

Primoz Ternik ◽

Rebeka Rudolf

Keyword(s):

Heat Transfer ◽

Rayleigh Number ◽

Base Fluid ◽

Volume Fraction ◽

Square Cavity ◽

Onset Of Convection ◽

Wide Range ◽

Water Based

The present work deals with the natural convection in a square cavity filled with the water-based Au nanofluid. The cavity is heated on the vertical and cooled from the adjacent wall, while the other two horizontal walls are adiabatic. The governing differential equations have been solved by the standard finite volume method and the hydrodynamic and thermal fields were coupled together using the Boussinesq approximation. The main objective of this study is to investigate the influence of the nanoparticles? volume fraction on the heat transfer characteristics of Au nanofluids at the given base fluid?s (i.e. water) Rayleigh number. Accurate results are presented over a wide range of the base fluid Rayleigh number and the volume fraction of Au nanoparticles. It is shown that adding nanoparticles in a base fluid delays the onset of convection. Contrary to what is argued by many authors, we show by numerical simulations that the use of nanofluids can reduce the heat transfer rate instead of increasing it.

Pool Boiling Characteristics of Metallic Nanofluids

Journal of Heat Transfer ◽

10.1115/1.4002597 ◽

2011 ◽

Vol 133 (11) ◽

Cited By ~ 14

Author(s):

K. Hari Krishna ◽

Harish Ganapathy ◽

G. Sateesh ◽

Sarit K. Das

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Boiling Heat Transfer ◽

Volume Fraction ◽

Pool Boiling ◽

Heat Fluxes ◽

Solid Particles ◽

Heater Surface ◽

Transfer Characteristics

Nanofluids, solid-liquid suspensions with solid particles of size of the order of few nanometers, have created interest in many researchers because of their enhancement in thermal conductivity and convective heat transfer characteristics. Many studies have been done on the pool boiling characteristics of nanofluids, most of which have been with nanofluids containing oxide nanoparticles owing to the ease in their preparation. Deterioration in boiling heat transfer was observed in some studies. Metallic nanofluids having metal nanoparticles, which are known for their good heat transfer characteristics in bulk regime, reported drastic enhancement in thermal conductivity. The present paper investigates into the pool boiling characteristics of metallic nanofluids, in particular of Cu-H2O nanofluids, on flat copper heater surface. The results indicate that at comparatively low heat fluxes, there is deterioration in boiling heat transfer with very low particle volume fraction of 0.01%, and it increases with volume fraction and shows enhancement with 0.1%. However, the behavior is the other way around at high heat fluxes. The enhancement at low heat fluxes is due to the fact that the effect of formation of thin sorption layer of nanoparticles on heater surface, which causes deterioration by trapping the nucleation sites, is overshadowed by the increase in microlayer evaporation, which is due to enhancement in thermal conductivity. Same trend has been observed with variation in the surface roughness of the heater as well.