Experimental investigation on boiling heat transfer characteristics of Al2O3-water nanofluids in swirl microchannels subjected to an acceleration force

Dong, Sujun; Jiang, Hongsheng; Xie, Yongqi; Wang, Xiaoming; Hu, Zhongliang; Wang, Jun

doi:10.1016/j.cja.2019.01.016

Cited by 18 publications

(6 citation statements)

References 24 publications

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“…Therefore, the HTCs increase continuously from low vapor quality to high vapor quality under gravity levels that are greater than 3 g. In addition, it can be seen from Figure 7 that with the increment of gravity levels, the trends of HTC variation are more and more reduced because of the asymmetric distribution of vapor phase in tube. The maximum value of HTC is that under Earth's gravity, and the average wall HTC of 9 g has 24% reduction compared to that of 1 g. Dong et al [1] tested flow boiling heat transfer of Al 2 O 3 -water nanofluids in swirl microchannels under gravity levels up to 9 g, and they also found that the HTC reduced with an increase of the acceleration magnitude. They considered the main reason was that the higher acceleration magnitude led to an increase of the local wall temperature; thus, the heat transfer performance was deteriorated.…”

Section: Model Validationmentioning

confidence: 99%

“…With the rapid development of aviation industry, more and more high precision with small volume equipment has been used in modern aircraft, especially heat exchanger, which needs a higher heat transfer efficiency with smaller volume [1][2][3][4]. Common liquids such as water, ethylene glycol (EG), and Freon are widely used for heat transfer up to now, while the efficiency of these pure liquids is not high enough in the heat transfer processes.…”

Section: Introductionmentioning

confidence: 99%

“…All above experimental investigations on the flow boiling heat transfer characteristics of nanofluids were conducted under normal gravity, and until now, only one literature presented by Dong et al [1] carried out the boiling heat transfer characteristics of nanofluids under hypergravity condition by using an acceleration simulating and control subsystem, which could simulate the acceleration magnitude up to 9 g. They used Al 2 O 3 -water nanofluid with volume concentrations varied from 0.07% to 0.1%. They found that the acceleration direction and magnitude had significant influences on the boiling heat transfer characteristics.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Numerical Simulation on the Boiling Flow Patterns of Al2O3-Water Nanofluid in Micro/Minichannel under Different Hypergravity Levels and Directions

Fang

2021

International Journal of Aerospace Engineering

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Due to the influence of hypergravity that has a significant impact on the performance of heat exchanger in aircraft, which is crucial for electronic equipment on the plane and life safeties of pilots and passengers, a numerical study is conducted using Fluent 20R2 software to investigate boiling flow patterns under different gravity levels and directions. In this study, the thermophysical properties of nanofluids are analyzed, and select the most suitable theoretical model of thermal conductivity, viscosity, and surface tension for present simulations. Choose the grid structure of 122,116 after independence check for grid. The VOF approach is employed for present simulation, and the standard κ − ε turbulence model with nonequilibrium wall function is used. The UDFs for mass and energy source terms and thermophysical properties of nanofluid are developed for calculating the HTC of nanofluid. There are three different gravity directions with gravity levels from 1 g to 9 g. The results show that the flow pattern becomes the stratified flow with the gravity levels increasing when the hypergravity direction is perpendicular to the flow direction, and the HTCs decrease with the increment of gravity levels. The vapor-phase transform to circular when the hypergravity direction is the same as the flow direction, and the HTCs of the second half of the tube are decreasing with the increasing gravity levels. On the contrary, the vapor phase is elongated when the hypergravity direction is opposite to the flow direction, and the HTCs show the enhanced tendency.

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Section: Model Validationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Numerical Simulation on the Boiling Flow Patterns of Al2O3-Water Nanofluid in Micro/Minichannel under Different Hypergravity Levels and Directions

Fang

2021

International Journal of Aerospace Engineering

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“…The most critical heat flux was found to be 1,515 kW/m 2 under a volume density of 0.05vol.% and was gradually reduced with the density of nanofluids and the size of L2 and L3-nanoparticles was 50 nm and decreased gradually. Donga et al [12] investigated an experiment on boiling heat transfer characteristics of Al2O3-water nanofluid in swirl micro channels subjected to an acceleration force. They applied three test sections with dissimilar geometric parameters.…”

Section: Nanofluids Enhancement On Boilingmentioning

confidence: 99%

Effect of Nanofluids on the Enhancement of Boiling Heat Transfer: A Review

Ali

Abedin

Ali

et al. 2021

IJEMM

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Boiling heat transfer can play a vital role in the two-phase flow applications. The analysis of the boiling hat transfer enhancement is of importance in such applications and the enhancement can be mostly conducted by using various active and passive techniques. One type of passive techniques is the enhancement of heat transfer by nanofluids. This article presents an extensive review on the effect of different nanofluids on the enhancement of heat transfer coefficient (HTC) and critical heat flux (CHF) for both pool as well as flow boiling. Nanoparticles addition to a working fluid is done arbitrarily to improve the thermophysical properties which in turn improves heat transfer rate. Numerous works have been done in the studies on nanofluid boiling. Among various nanoparticles, the most frequently used nanoparticles are Al2O3 and TiO2. In the case of binary nanoparticles, the most commonly used combination is Al2O3 and TiO2. After reviewing the relevant literatures, it is found that for pool boiling, the maximum HTC is increased to 138% for TiO2 nanoparticles and the maximum CHF is increased to 274.2% for MWCNTs. Conversely, in flow boiling the maximum HTC is increased to 126% for ZnO nanoparticles and the maximum CHF increased to as 100% for GO nanoparticles. In addition, when two or more nanoparticles in succession or binary nanofluids are used the CHF in pool boiling increased up to 100% for Al2O3 and TiO2 as well as the CHF in flow boiling increased up to 100% for Al2O3, ZnO, and Diamond. Though the information of the coefficient of heat transfer and the critical heat flux varied for different nanofluids and vary from experiment to experiment for each of the nanofluids. This variation happens because the coefficient of heat transfer and the critical heat flux in boiling is dependent upon several factors.

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“…Thermally–driven phase change processes are often encountered in various scientific or industrial configurations, including aerospace, power plants, food and other chemical or petrochemical processes. There has been a resurgence of interest and study in the use of thermal phase change processes in conjunction with nanofluids, notably in heat transfer applications involving the flow boiling of nanofluids in recent years [ 1 , 2 ]. Flow boiling is an effective cooling method because the formation of bubbles may remove a significant amount of energy while simultaneously driving the flow due to the density differential.…”

Section: Introductionmentioning

confidence: 99%

A Benchmark Evaluation of the isoAdvection Interface Description Method for Thermally–Driven Phase Change Simulation

2022

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A benchmark study is conducted using isoAdvection as the interface description method. In different studies for the simulation of the thermal phase change of nanofluids, the Volume of Fluid (VOF) method is a contemporary standard to locate the interface position. One of the main drawbacks of VOF is the smearing of the interface, leading to the generation of spurious flows. To solve this problem, the VOF method can be supplemented with a recently introduced geometric method called isoAdvection. We study four benchmark cases that show how isoAdvection affects the simulation results and expose its relative strengths and weaknesses in different scenarios. Comparisons are made with VOF employing the Multidimensional Universal Limiter for Explicit Solution (MULES) limiter and analytical data and experimental correlations. The impact of nanoparticles on the base fluid are considered using empirical equations from the literature. The benchmark cases are 1D and 2D boiling and condensation problems. Their results show that isoAdvection (with isoAlpha reconstruct scheme) delivers a faster solution than MULES while maintaining nearly the same accuracy and convergence rate in the majority of thermal phase change scenarios.

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Experimental investigation on boiling heat transfer characteristics of Al2O3-water nanofluids in swirl microchannels subjected to an acceleration force

Cited by 18 publications

References 24 publications

Numerical Simulation on the Boiling Flow Patterns of Al2O3-Water Nanofluid in Micro/Minichannel under Different Hypergravity Levels and Directions

Numerical Simulation on the Boiling Flow Patterns of Al2O3-Water Nanofluid in Micro/Minichannel under Different Hypergravity Levels and Directions

Effect of Nanofluids on the Enhancement of Boiling Heat Transfer: A Review

A Benchmark Evaluation of the isoAdvection Interface Description Method for Thermally–Driven Phase Change Simulation

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