An experimental investigation on rheological properties and heat transfer performance of MWCNT-water nanofluid flow inside vertical tubes
TL;DR: In this paper, the authors investigated the convective heat transfer and friction factor of MWCNT-water nanofluids inside a vertical circular tube and proposed two correlations to predict the Nusselt number and the friction factor.
About: This article is published in Applied Thermal Engineering.The article was published on 2016-08-05. It has received 28 citations till now. The article focuses on the topics: Nanofluid & Convective heat transfer.
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TL;DR: In this paper, the authors present the results of an experimental investigation on the heat transfer characteristics of multi-walled carbon nanotube aqueous nanofluids inside a countercurrent double-pipe heat exchanger using porous media.
Abstract: This paper presents the results of an experimental investigation on the heat transfer characteristics of multi-walled carbon nanotube aqueous nanofluids inside a countercurrent double-pipe heat exchanger using porous media. Aluminum porous media (e = 67%) were used because of the construction of the medium, with porous plate media at the center of the inner tube and with three porous plates on the walls of the inner tube. The effects of operating parameters including flow rate (4600 < Re < 7600), mass fractions of nanofluids (0.04–0.25 mass%), and inlet temperature of nanofluids (Tin = 50 °C) on the heat transfer coefficient were investigated. The results indicate that imposing the plate porous media increases the heat transfer coefficient significantly, and the highest increase in the heat transfer coefficient is 35% which is obtained in the test of the lowest mass fraction (0.04 mass%) with three-plate porous media in the experiment range. As the mass fractions increased, the value of heat transfer enhancement assisted by porous media gradually decreased. Also the lower range 100 (L h−1) of the volume flow rate has a powerful enhancement on the enhancement coefficient, while the higher ranges 300 (L h−1) have low influence.
124 citations
TL;DR: In this article, the rheological behavior of MgO-Water nanofluid at different temperatures ranging from 25°C to 60°C and different volume fractions ranging from 0.07% to 1.25% has been examined.
121 citations
01 Feb 2021
TL;DR: In this paper, the impact of nanofluid on thermo-hydraulic performance of thermal devices is discussed. But, the authors do not consider the effect of nanoparticles on the thermal properties of the base fluid.
Abstract: Nanofluid is considered to be a new generation heat transfer medium which has attracted significant attention from the research community for the past two decades due to its reported high effectiveness in various heat transfer applications. Dispersed solid nanoparticles with enhanced thermal conductivity in base fluid possess substantial competence in augmenting thermal performance at the expense of moderate pumping power. This inclusive study elaborates the impact of nanofluids on thermo-hydraulic performance of thermal devices in order to ensure the appropriate selection and implementation of nanofluids in various engineering thermal devices. Inclusion of nanofluid as heat transfer fluid in various systems requiring high heat transfer rate e.g. solar thermal conversion systems, HVAC systems, electronic equipment, heat exchangers, nuclear reactors have imparted greater role in reducing negative impacts of climate change. The influence of size, concentration, type and shape of nanoparticles, working temperature, compound passive techniques and magnetic field effect on heat transfer and pressure drop performance of nanofluids are extensively discussed along with the drawbacks of nanofluids such as formation of fouling on heat transfer surfaces. This comprehensive review will be beneficial for engineers, researchers, and academics to commend the significance of various nanofluids and comprehend their remarkable impact on various heat transfer applications.
100 citations
TL;DR: In this paper, the authors present a comprehensive and up-to-date review of carbon nanotubes (CNTs) being applied in various heat transfer (convective and boiling) and mass transfer systems such as heat exchangers and separators.
Abstract: The pursuit of superior working fluids for heat and mass transfer systems in the industry is on the rise, inspired by not only to maximize revenue but also to accommodate heat dissipation or chemical separation under extreme conditions The addition of a small amount of nanoparticle, a product called nanofluid, has been initiated over the last decade In particular, researchers have employed carbon nanotubes (CNTs) into conventional fluids as their preferred nanoparticles due to the merits of having a remarkable thermal conductivity compared to other nanoparticles Here, we present a comprehensive and up to date review of this incredible fluid being applied in various heat transfer (convective and boiling) and mass transfer systems such as heat exchangers and separators Other critical parameters associated with the practicality of the CNT nanofluids such as pumping power and efficiency are also discussed We surveyed a remarkable range of results of some of the heat and mass transfer studies that strongly depend on the inherent CNT nanofluid characteristics and operating conditions such as CNT treatment, size, concentration, Reynolds number, and so on A major conclusion that can be drawn from this review is the significantly higher heat transfer coefficient at lower pressure drop or pumping power of the CNT nanofluid compared to other nanofluids, which implied better thermal performance of the heat transfer system Besides that, the concentration of CNT is the influential factor to achieve optimum boiling heat transfer while the mass transfer performance of the CNT nanofluid is moderately good against other nanofluids Additionally, CNT treatment using covalent functionalization is crucial for the overall stability and performance of the CNT nanofluid However, several issues that inhibit their widespread use such as possible corrosion-erosion in systems, lack of risk assessments, and high cost of CNT nanofluid must be thoroughly addressed in future studies
91 citations
TL;DR: In this article, an experimental investigation of the thermohydraulic performance of nanofluids, composed of graphene and silver nanoparticles with a binary mixture of equal parts of water and ethylene glycol (50:50) as a base fluid, in automotive radiators was presented.
90 citations
References
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Journal Article•
7,568 citations
"An experimental investigation on rh..." refers methods in this paper
...To examine the accuracy of the experimental data, the uncertainty of the major heat transfer parameters has been conducted using the proposed equation of Kline and McClintock [25]....
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01 Jan 1995
7,263 citations
"An experimental investigation on rh..." refers background in this paper
...In this regard, Choi [1] was one of the first researchers who developed nanoparticles and then dispersed them in a fluid that he called nanofluid....
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...Choi et al. [3] conducted experiments on the thermal conductivity of CNT-engine oil nanofluids and reported thermal conductivity enhancement of 160% for 1.0% vol of CNT nanofluids....
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TL;DR: In this article, an innovative new class of heat transfer fluids can be engineered by suspending metallic nanoparticles in conventional heat-transfer fluids, which are expected to exhibit high thermal conductivities compared to those of currently used heat transfer fluid, and they represent the best hope for enhancing heat transfer.
Abstract: Low thermal conductivity is a primary limitation in the development of energy-efficient heat transfer fluids that are required in many industrial applications. In this paper we propose that an innovative new class of heat transfer fluids can be engineered by suspending metallic nanoparticles in conventional heat transfer fluids. The resulting {open_quotes}nanofluids{close_quotes} are expected to exhibit high thermal conductivities compared to those of currently used heat transfer fluids, and they represent the best hope for enhancement of heat transfer. The results of a theoretical study of the thermal conductivity of nanofluids with copper nanophase materials are presented, the potential benefits of the fluids are estimated, and it is shown that one of the benefits of nanofluids will be dramatic reductions in heat exchanger pumping power.
4,634 citations
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TL;DR: In this article, the physical concepts and methodologies of heat and mass transfer are explained for advanced undergraduate engineering majors, using a systematic method for problem solving and discusses the relationship of heat transfer to many important practical applications through examples and problems.
Abstract: This book, designed for advanced undergraduate engineering majors, explains the physical concepts and methodologies of heat and mass transfer. It uses a systematic method for problem solving and discusses the relationship of heat and mass transfer to many important practical applications through examples and problems. A and significant contribution is the extensive use of the First Law of thermodynamics.
4,113 citations
01 Jan 1976
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"An experimental investigation on rh..." refers methods in this paper
...Experimental results for water under constant heat flux conditions compared with those predicted by Gnielinski [26] equation for the turbulent flow, given by the following equation:...
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...Experimental results for water under constant heat flux conditions compared with those predicted by Gnielinski [26] equation for the turbulent flow, given by the following equation: Nud ¼ f=8ðRe 1000ÞPr 1þ 12:7 ffiffi f 8 q Pr 2 3 1 ð6Þ Eq....
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