Preface: Progress in Heat Transfer Enhancement Research

The purpose of this review article is to summarize the important published articles on the enhancement of the convection heat transfer with Nanofluids. Over the last 2-3 decades, there has been intensive research into the behavior of substances that contain extremely small particles. Nanotechnology is the science and engineering of working at the Nano-scale, where the individual particles are 1-100 nanometers in size. It's hard to imagine the size of nanoparticles, but there are about 2, 54, 00,000 nanometers in an inch. Nanofluids which are less than even a micron (nearly 10-9 times smaller) in diameter, highly reactive and efficient material which can be used to increase factor like rate of heat transfer, thermal conductivity of any metal or material, they are that much reactive and strong. The thermal conductivity increases with decreasing the grain size of the material. As the thermal conductivity increases the heat transfer rate increases.

Nanofluids are a fluids containing nanometer-sized particles, called nanoparticles. These fluids are Suspension of nanoparticles in customary fluids. Nanofluids have been the subject of escalated think about worldwide since spearheading analysts as of late found the odd thermal conduct of these fluids. The improvement of heat exchange utilizing nanofluids have been utilized as one of the detached heat move systems in a few heat exchange applications. It is considered to have extraordinary potential for heat exchange improvement and are exceptionally fit to application in heat exchange forms like microelectronics, energy units, pharmaceutical procedures, and half and half fueled motors, motor cooling/vehicle thermal administration, local icebox, chiller, heat exchanger, and in heater vent gas temperature decrease. This survey covers the upgrade of heat exchange by utilizing nanofluids and potential utilizations of nanofluids. This paper exhibits a refreshed audit of the heat exchange utilizations of nanofluids to create bearings for future work on the grounds that the writing around there is spread over a wide scope of controls, including heat exchange, material science, physical science, substance designing and engineered science.

This paper gives a detailed literature study and scrutiny into the results of the research and development, applications of nanofluids in heat transfer. Nanofluid is a comparatively new technology, the studies on nanofluid are not longer. Experimental data were reviewed in this study related to the enhancement of the thermal conductivity and convective heat transfer of nanofluids relative to conventional heat transfer fluids, and assessments were made as parameters of volume concentration, material, particle size, , base fluid material, temperature, particle shape, additive, and pH were taken into account, experimental results from so many researcher were used together when assessing data. The current state of knowledge is presented as well as areas where the data are presently inconclusive or conflicting. Heat transfer enhancement can be achieved using nanofluids is to be in the 15–40% range, with a few situations resulting in orders of magnitude enhancement

Journal of Complex Flow, 2024

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Nanofluids are quasi single phase medium containing stable colloidal dispersion of ultrafine or nanometric metallic or ceramic particles in a given fluid. Nanofluids possess immense potential of application to improve heat transfer and energy efficiency in several areas including vehicular cooling in transportation, power generation, defense, nuclear, space, microelectronics and biomedical devices. In the present contribution, a brief overview has been presented to provide an update on the historical evolution of this concept, possible synthesis routes, level of improvements reported, theoretical understanding of the possible mechanism of heat conduction by nanofluid and scopes of application. According to this review, the future developments of these technologies are discussed. In order to put the nanofluid heat transfer technologies into practice, fundamental studies are greatly needed to understand the physical mechanisms

Nanofluids are a fluids containing nanometer-sized particles, called nanoparticles. These fluids are Suspension of nanoparticles in conventional fluids. Nanofluids have been the subject of intensive study worldwide since pioneering researchers recently discovered the anomalous thermal behavior of these fluids. The enhancement of heat transfer using nanofluids have been used as one of the passive heat transfer techniques in several heat transfer applications. It is considered to have great potential for heat transfer enhancement and are highly suited to application in heat transfer processes like microelectronics, fuel cells, pharmaceutical processes, and hybrid-powered engines, engine cooling/vehicle thermal management, domestic refrigerator, chiller, heat exchanger, and in boiler flue gas temperature reduction. This review covers the enhancement of heat transfer by using nanofluids and potential applications of nanofluids. This paper presents an updated review of the heat transfer applications of nanofluids to develop directions for future work because the literature in this area is spread over a wide range of disciplines, including heat transfer, material science, physics, chemical engineering and synthetic chemistry.

Heat Transfer Enhancement with Nanofluids, 2015

147 pages A nanofluid is the suspension of nanoparticles in a base fluid. Nanofluids are promising for heat transfer enhancement due to their high thermal conductivity. Presently, discrepancy exists in nanofluid thermal conductivity data in the literature, and enhancement mechanisms have not been fully understood yet. In the first part of this study, a literature review of nanofluid thermal conductivity is performed. Experimental studies are discussed through the effects of some parameters such as particle volume fraction, particle size, and temperature on conductivity. Enhancement mechanisms of conductivity are summarized, theoretical models are explained, model predictions are compared with experimental data, and discrepancies are indicated. Nanofluid forced convection research is important for practical application of nanofluids. Recent experiments showed that nanofluid heat transfer enhancement exceeds the associated thermal conductivity enhancement, which might be explained by thermal dispersion, which occurs due to random motion of nanoparticles. In the second part of the study, to examine the validity of a thermal dispersion model, hydrodynamically developed, thermally developing laminar Al2O3/water nanofluid flow inside a circular tube under constant wall v temperature and heat flux boundary conditions is analyzed by using finite difference method with Alternating Direction Implicit Scheme. Numerical results are compared with experimental and numerical data in the literature and good agreement is observed especially with experimental data, which indicates the validity of the thermal dispersion model for explaining nanofluid heat transfer. Additionally, a theoretical analysis is performed, which shows that usage of classical correlations for heat transfer analysis of nanofluids is not valid.

Renewable and Sustainable Energy Reviews, 2019

This paper presents a critical review of heat transfer applications of nanofluids. The effects of nanoparticle concentration, size, shape, and nanofluid flow rate on Nusselt number, heat transfer coefficient, thermal conductivity, thermal resistance, friction factor and pressure drop from numerous studies reported recently are presented. Effects of various geometric parameters on heat transfer enhancement of system using nanofluids have also been reviewed. Heat transfer devices covered in this paper include radiators, circular tube heat exchangers, plate heat exchangers, shell and tube heat exchangers and heat sinks. Various correlations used for experimental validation or developed in reviewed studies are also compiled, compared and analyzed. The pros and cons associated to the applications of nanofluids in heat transfer devices are presented in details to determine the future direction of research in this arena.

2016

Mr. Sumit G. Wani.1 Dr.L.V.Kamble2 M.E.(Heat Power), Dr.DY Patil SOEA,Ambi, Talegaon,Pune,Maharshtra 1 H.O.D. Department of Mechanical Engineering, Dr.DY Patil SOEA,Ambi, Talegaon,Pune,Maharshtra2 ---------------------------------------------------------------------***----------------------------------------------------------------- Abstract: There has been increasing interest in nanofluid and its use in heat transfer enhancement. Nanofluids are suspensions of nanoparticles in fluids that show significant enhancement of their properties at modest nanoparticle concentrations. Nanofluids are quasi single phase medium containing stable colloidal dispersion of ultrafine or nanometric metallic or ceramic particles in a given fluid. This article covers recent advances in the last decade by researchers in heat transfer enhancement with nanofluids as the working fluid. A brief overview has been presented to understand the evolution of this concept, possible mechanism of heat conduction by n...

Applied Thermal Engineering, 2006

Heat transfer enhancement capabilities of coolants with suspended metallic nanoparticles inside typical radial flow cooling systems are numerically investigated in this paper. The laminar forced convection flow of these nanofluids between two coaxial and parallel disks with central axial injection has been considered using temperature dependent nanofluid properties. Results clearly indicate that considerable heat transfer benefits are possible with the use of these fluid/solid particle mixtures. For example, a Water/Al 2 O 3 nanofluid with a volume fraction of nanoparticles as low as 4% can produce a 25% increase in the average wall heat transfer coefficient when compared to the base fluid alone (i.e., water). Furthermore, results show that considerable differences are found when using constant property nanofluids (temperature independent) versus nanofluids with temperature dependent properties. The use of temperature-dependent properties make for greater heat transfer predictions with corresponding decreases in wall shear stresses when compared to predictions using constant properties. With an increase in wall heat flux, it was found that the average heat transfer coefficient increases whilst the wall shear stress decreases for cases using temperature-dependent nanofluid properties.