Selection of suitable heat transfer fluid for heat dissipation is an important consideration in the design of heat exchanging systems. Nanofluid, a colloidal mixture made of a base fluid and a nanoparticle, is a new generation of heat transfer fluids becoming a high potential fluid in heat transfer applications due to enhanced thermal conductivity. Research studies about nanofluids are on the rise owing to the mounting interest and demand for nanofluids as heat transfer fluids in a wide variety of applications. Recently, nanofluid technology has a new dimension of impregnating two or more nanoparticles in base fluids, namely hybrid or composite nanofluids. This paper reviews the preparation of metal and metal oxides nanofluids and hybrid nanofluids and the various techniques used to study the physical and chemical characteristics of nanofluids. Thermo-physical and heat transfer properties of nanofluids including the improved thermal conductivity, viscosity and specific heat models for nanofluids are presented. Finally, various application areas of nanofluids, such as transportation, electronic cooling, energy storage, mechanical applications etc. are discussed.

A review on preparation, characterization, properties and applications of nanofluids

Continued miniaturization and demand for high-end performance of electronic devices and appliances have led to dramatic increase in their heat flux generation. Consequently, conventional coolants and cooling approaches are increasingly falling short in meeting the ever-increasing cooling needs and challenges of those high heat generating electronic devices. This study provides a critical review of traditional and emerging cooling methods as well as coolants for electronics. In addition to summarizing traditional coolants, heat transfer properties and performances of potential new coolants such as nanofluids are also reviewed and analyzed. With superior thermal properties and numerous benefits nanofluids show great promises in fulfilling the cooling demands of high heat generating electronic devices. It is believed that applications of such novel coolants in emerging techniques like micro-channels and micro-heat pipes can revolutionize cooling technologies for electronics in the future.

A critical review of traditional and emerging techniques and fluids for electronics cooling

Preparation and evaluation of stable nanofluids for heat transfer application: A review

In many applications, there is a critical need for enhancing the poor thermal conductivity of conventional fluids in order to develop efficient heat transfer fluids. This requirement can be met through dispersing nanometric particles in a given base fluid such as water, ethylene glycol, oil or air. The resulting nanofluids enhanced thermal conductivity of the base fluids. In order to evaluate this enhancement, nanofluid thermal conductivity is required to be measured. Several methods and techniques are covered in the present contribution. In addition, enhancements recorded experimentally are reviewed and summarized. Different parameters affecting on such enhancement are covered, including: nanoparticle concentration, size, shape and thermal conductivity. In addition, base fluid type, nanofluid bulk temperature and dispersion techniques are also covered parameters. However, nanofluids have the potential to contribute in several practical applications including solar thermal, transportation, electronic cooling, medical, detergency and military applications. In the present work, a brief overview of evolution in the use of nanofluids in some applications has been presented. According to this contribution, there is a critical need for further fundamental and applications of nanofluids studies in order to understand the physical mechanisms of using nanofluids as well as explore different aspects of applications of nanofluids.

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Experimental studies of nanofluid thermal conductivity enhancement and applications: A review

Widespread approaches to fabricate surfaces with robust micro- and nanostructured topographies have been stimulated by opportunities to enhance interface performance by combining physical and chemical effects. In particular, arrays of asymmetric surface features, such as arrays of grooves, inclined pillars, and helical protrusions, have been shown to impart unique anisotropy in properties including wetting, adhesion, thermal and/or electrical conductivity, optical activity, and capability to direct cell growth. These properties are of wide interest for applications including energy conversion, microelectronics, chemical and biological sensing, and bioengineering. However, fabrication of asymmetric surface features often pushes the limits of traditional etching and deposition techniques, making it challenging to produce the desired surfaces in a scalable and cost-effective manner. We review and classify approaches to fabricate arrays of asymmetric 2D and 3D surface features, in polymers, metals, and ceramics. Analytical and empirical relationships among geometries, materials, and surface properties are discussed, especially in the context of the applications mentioned above. Further, opportunities for new fabrication methods that combine lithography with principles of self-assembly are identified, aiming to establish design principles for fabrication of arbitrary 3D surface textures over large areas.

Engineering of Micro‐ and Nanostructured Surfaces with Anisotropic Geometries and Properties

Due to rapid growth in semiconductor technology, there is a continuous increase of the system power and the shrinkage of size. This resulted in inevitable challenges in the field of thermal management of electronics to maintain the desirable operating temperature. The present paper reviews the literature dealing with various aspects of cooling methods. Included are papers on experimental work on analyzing cooling technique and its stability, numerical modeling, natural convection, and advanced cooling methods. The issues of thermal management of electronics, development of new effective cooling schemes by using advanced materials and manufacturing methods are also enumerated in this paper. .

/pdf/thermal-management-of-electronics-a-review-of-literature-5c1q8pl1w8.pdf

Thermal management of electronics: A review of literature

Nanofluids are colloidal mixtures of nanometric metallic or ceramic particles
 in a base fluid, such as water, ethylene glycol or oil. Nanofluids possess
 immense potential to enhance the heat transfer character of the original
 fluid due to improved thermal transport properties. In this article, a brief
 overview has been presented to address the unique features of nanofluids,
 such as their preparation, heat transfer mechanisms, conduction and
 convection heat transfer enhancement, etc. In addition, the article
 summarizes the experimental and theoretical work on pool boiling in
 nanofluids and their applications.

/pdf/heat-transfer-enhancement-using-nanofluids-an-overview-49w4vimyva.pdf

HEAT TRANSFER ENHANCEMENT USING NANOFLUIDS An Overview

Anilinium D-Tartrate (ADT) was subjected to study the mechanical behaviour of crystal. The microhardness study reveals the mechanical strength of the grown crystal. The Vicker’s and Knoop hardness studies were performed to understand the mechanical behavior of the Anilinium D-Tartrate crystals. The Vicker’s and Knoop microhardness numbers (HV and HK) for the crystal were found for different loads. It is found that these numbers increase with an increase in the load. The Mayer’s index (n) was found to be greater than 1.6 predicting a soft-material category. The fracture toughness value (Kc), was determined from the measurements of the crack length. The brittleness indices (Bi) were found for the grown crystals. Using Wooster’s empirical relation, the elastic stiffness constant (C11) was calculated from the Vicker’s hardness values at different loads. The Young’s modulus was also calculated from Knoop microhardness values.

/pdf/a-study-of-mechanical-behaviour-of-anilinium-d-tartrate-4ev6y2etgh.pdf

A Study of Mechanical Behaviour of Anilinium D-Tartrate Single Crystal

An experimental study on Thermosyphon Integrated Heat Sink (TIHS) for CPU cooling has been carried out for both natural and forced convection to analyze the performance characteristics of the CPU cooling module (TIHS) at steady state condition. A thermal model based on the experimental values has been developed to study the thermal behavior of Thermosyphon Integrated Heat Sink during CPU cooling. The thermal model is employed to determine the actual heat transfer and the effectiveness of the CPU cooling module and compared it with the conventional cooling method and found that there is an appreciable improvement in the proposed CPU cooling module.

/pdf/performance-evaluation-of-thermosyphon-integrated-heat-sink-2pwfnm1a20.pdf

Performance evaluation of thermosyphon integrated heat sink for cpu cooling

ABSTRACT Guava is a fruit grown predominantly in the tropical and subtropical regions of the world. Its skin is thin and soft. Although postharvest handling and transportation of fruits are unavoidable, hand harvesting is preferred to avoid physical injuries. Visually identifying internal damage is a laborious and time-consuming task. In this study, 4129 thermal and digital images of guava fruits were collected. A digital image-based convolution neural network (CNN) model was developed to classify the quality of damaged and diseased fruits. The surface temperatures of all three levels of maturity-indexed and damaged fruits were measured using thermal images. During the storage period, the temperature of the immature fruits was less than half of the mature fruits. Because the architecture was trained on dehydrated and diseased guava, it accurately predicted fruit quality. The prediction accuracy of the developed CNN model was approximately 99.92%. GRAPHICAL ABSTRACT

Shanmuga Sundaram Anandan

Papers

Thermal management of electronics: A review of literature

HEAT TRANSFER ENHANCEMENT USING NANOFLUIDS An Overview

A Study of Mechanical Behaviour of Anilinium D-Tartrate Single Crystal

Performance evaluation of thermosyphon integrated heat sink for cpu cooling

Guava fruit (Psidium guajava) damage and disease detection using deep convolutional neural networks and thermal imaging