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Heat transfer

About: Heat transfer is a research topic. Over the lifetime, 181795 publications have been published within this topic receiving 2923586 citations. The topic is also known as: heat exchange.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the effects of concentration of carbon nanotubes and temperature on effective thermal conductivity were investigated, and it was found that effective thermal conduction increased with increasing concentration of the carbon-nanotubes, and the dependence was nonlinear even at very low concentrations.
Abstract: This work is concerned with the effective thermal conductivity of aqueous suspensions of multiwalled carbon nanotubes (nanofluids). Stable nanofluids were made using sodium dodecylbenzene sulfonate as the dispersant. The effects of concentration of carbon nanotubes and temperature on effective thermal conductivity were investigated. It was found that effective thermal conductivity increased with increasing concentration of carbon nanotubes, and the dependence was nonlinear even at very low concentrations, which was different from the results for metal/metal oxide nanofluids. The effective thermal conductivity increased with increasing temperature, and the dependence was also nonlinear. At temperatures lower than ∼30 ◦ C, approximately linear dependence of the thermal conductivity enhancement on temperature was seen, but the dependence tended to level off above ∼30◦C. A comparison between the results of this work and those of published studies showed a large discrepancy in the effective thermal conductivity of carbon nanotube nanofluids. Differences in the interfacial resistances and thermal conductivities of carbon nanotubes used in these studies were proposed to be the main reasons. The experimental results were also compared with some classical macroscopic models for thermal conductivity of homogenous mixtures containing micrometer- or millimeter-sized particles. It was shown that the macroscopic models were inadequate for the prediction of the effective thermal conductivity of nanofluids. Analysis of possible mechanisms for thermal conduction enhancement suggested that networking of carbonnanotubes was likely to be responsible for the observed high effective thermal conductivity of carbon-nanotube nanofluids. Experiments at a temperature above 60‐70 ◦ C showed that the dispersant failed, which led to destabilization of nanofluids.

458 citations

Journal ArticleDOI
TL;DR: In this article, a criterion for bubble initiation from a gas filled cavity on a surface in contact with a superheated layer of liquid was developed, and it was found that the temperature of bubble initiation on a given surface is a function of the temperature conditions in the liquid surrounding the cavity as well as the surface properties themselves.

457 citations

Journal ArticleDOI
TL;DR: In this paper, an experimental energy storage system has been designed using a horizontal concentric tube heat exchanger incorporating a medium temperature phase change material (PCM) Erythritol, with a melting point of 117.7°C.

456 citations

Journal ArticleDOI
TL;DR: The turbulent convective heat transfer behavior of alumina (Al 2 O 3 ) and zirconia (ZrO 2 ) nanoparticle dispersions in water is investigated experimentally in a flow loop with a horizontal tube test section at various flow rates (9000
Abstract: The turbulent convective heat transfer behavior of alumina (Al 2 O 3 ) and zirconia (ZrO 2 ) nanoparticle dispersions in water is investigated experimentally in a flow loop with a horizontal tube test section at various flow rates (9000

455 citations

Journal ArticleDOI
TL;DR: In this paper, the convective heat transfer coefficient and friction factor for fully developed turbulent flow of MWCNT-Fe3O4/water hybrid nanofluids flowing through a uniformly-heated-atconstant-heat-flux circular tube are estimated.

453 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20235,737
202210,641
20217,860
20208,182
20198,826
20188,737