Experimental study of thermo-convection performance of hybrid nanofluids of Al2O3-MWCNT/water in a differentially heated square cavity
Experimental study of thermo-convection performance of hybrid nanofluids of Al2O3-MWCNT/water in a differentially heated square cavity
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DOI：
10.1016/j.ijheatmasstransfer.2019.119072
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发表时间：
2020-02-01
影响因子：
5.2
通讯作者：
Meyer, J. P.
中科院分区：
文献类型：
--
作者：
Giwa, S. O.;Sharifpur, M.;Meyer, J. P.
混合纳米流体是一类新型的纳米流体，其热性能和流动性能优于单颗粒纳米流体。然而，实验研究的自然对流的混合纳米流体在封闭的领域是非常罕见的。本文研究了0.1vol%的Al_2O_3-MWCNT/水纳米流体在不同双纳米粒子重量百分比（Al_2O_3：MWCNT：80：20，60：40，40：60和20：80）下的自然对流。考虑在不同温度梯度（20 ° C-50 ° C）下的Nu（av）、h（av）、Ra和Q（av）。在20 ° C-50 ° C的温度范围内实验测量了稳定的纳米流体和基础流体的粘度和热导率。对所获得的这些性能的实验数据进行了研究。在这项工作中考虑的Ra的范围是1.65 × 10（8）-3.80 × 10（8）。Ra和Nu（av）之间存在直接关系。观察到纳米流体中的双纳米颗粒的温度梯度和重量百分比增加Nu（av）、h（av）和Q（av）。具有60：40重量%的Al 2 O3和MWCNT纳米颗粒的混合纳米流体被鉴定为在各种温度梯度下具有Ra、Nu（av）、h（av）和Q（av）的最高值。此外，在Δ T = 50 ℃时，相对于基础流体，Nu（av）、h（av）和Q（av）分别记录了16.2%、20.5%和19.4%的最大增强。Al 2 O3-MWCNT/水纳米流体在方形腔中的接合显示出改善的自然对流性能。一个新的相关Ra和双纳米粒子的比例已被开发用于预测Nu（av）。这项研究的结果进一步证实了混合纳米流体比单颗粒纳米流体所提供的优势。(C)2019爱思唯尔有限公司版权所有。
Hybrid nanofluids as a new class of nanofluids known for their improved thermal and flow properties over single-particle nanofluids. However, experimental studies on the natural convection of hybrid nanofluids in enclosures are very scarce in the public domain. This paper investigates the natural convection of Al2O3-MWCNT/water nanofluids at various bi-nanoparticles' percent weights (Al2O3:MWCNT: 80:20, 60:40, 40:60, and 20:80) for 0.1 vol% in a square cavity. The Nu(av), h(av), Ra and Q(av) at varying temperature gradients (20 degrees C-50 degrees C) were considered. The viscosity and thermal conductivity of the stable nanofluids and base fluid were experimentally measured at a temperature range of 20 degrees C-50 degrees C. The obtained experimental data for these properties were engaged in the study. The range of Ra considered in this work was 1.65 x 10(8)-3.80 x 10(8). A direct relationship was noticed between Ra and Nu(av). Temperature gradient and percent weight of bi-nanoparticles in the nanofluids were observed to augment Nu(av), h(av), and Q(av). The hybrid nanofluid with 60:40 wt% of Al2O3 and MWCNT nanoparticles was identified to have the highest value for Ra, Nu(av), h(av), and Q(av) at various temperature gradients. Furthermore, maximum enhancements of 16.2%, 20.5%, and 19.4% were recorded for Nu(av), h(av), and Q(av), respectively, at Delta T = 50 degrees C, in relation to the base fluid. The engagement of Al2O3-MWCNT/water nanofluids in a square cavity has shown improved natural convection performance. A new correlation as related to Ra and bi-nanoparticles ratio has been developed for predicting Nu(av). Results from this study further corroborate the advantage afforded by hybrid nanofluids over single-particle nanofluids. (C) 2019 Elsevier Ltd. All rights reserved.