scholarly journals Analysis of the Parameters Required to Properly Define Nanofluids for Heat Transfer Applications

Fluids ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 65
Author(s):  
Sergio Bobbo ◽  
Bernardo Buonomo ◽  
Oronzio Manca ◽  
Silvio Vigna ◽  
Laura Fedele
Keyword(s):  
Heat Transfer ◽  
Tio2 Nanoparticles ◽  
Thermophysical Properties ◽  
Base Fluid ◽  
Minimum Amount ◽  
Literature Analysis ◽  
Amount Of Information

Nanofluids are obtained by dispersing nanoparticles and dispersant, when present, in a base fluid. Their properties, in particular their stability, however, are strictly related to several other parameters, knowledge of which is important to reproduce the nanofluids and correctly interpret their behavior. Due to this complexity, the results appear to be frequently unreliable, contradictory, not comparable and/or not repeatable, in particular for the scarcity of information on their preparation. Thus, it is essential to define what is the minimum amount of information necessary to fully describe the nanofluid, so as to ensure the possibility of reproduction of both their formulation and the measurements of their properties. In this paper, a literature analysis is performed to highlight what are the most important parameters necessary to describe the configuration of each nanofluid and their influence on the nanofluid’s properties. A case study is discussed, analyzing the information reported and the results obtained for the thermophysical properties of nanofluids formed by water and TiO2 nanoparticles. The aim is to highlight the differences in the amount of information given by the different authors and exemplify how results can be contradictory. A final discussion gives some suggestions on the minimum amount of information that should be given on a nanofluid to have the possibility to compare results obtained for similar nanofluids and to reproduce the same nanofluid in other laboratories.

scholarly journals Enhancement of heat transfer coefficient multi-metallic nanofluid with ANFIS modeling for thermophysical properties

2015 ◽  
Vol 19 (5) ◽  
pp. 1613-1620 ◽  
Author(s):  
Hyder Balla ◽  
Shahrir Abdullah ◽  
Wan Faizal ◽  
Rozli Zulkifli ◽  
Kamaruzaman Sopian
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Thermophysical Properties ◽  
Dynamic Viscosity ◽  
Base Fluid ◽  
Volume Fractions ◽  
The Heat Transfer Coefficient ◽  
Cu And Zn

Cu and Zn-water nanofluid is a suspension of the Cu and Zn nanoparticles with the size 50 nm in the water base fluid for different volume fractions to enhance its Thermophysical properties. The determination and measuring the enhancement of Thermophysical properties depends on many limitations. Nanoparticles were suspended in a base fluid to prepare a nanofluid. A coated transient hot wire apparatus was calibrated after the building of the all systems. The vibro-viscometer was used to measure the dynamic viscosity. The measured dynamic viscosity and thermal conductivity with all parameters affected on the measurements such as base fluids thermal conductivity, volume factions, and the temperatures of the base fluid were used as input to the Artificial Neural Fuzzy inference system to modeling both dynamic viscosity and thermal conductivity of the nanofluids. Then, the ANFIS modeling equations were used to calculate the enhancement in heat transfer coefficient using CFD software. The heat transfer coefficient was determined for flowing flow in a circular pipe at constant heat flux. It was found that the thermal conductivity of the nanofluid was highly affected by the volume fraction of nanoparticles. A comparison of the thermal conductivity ratio for different volume fractions was undertaken. The heat transfer coefficient of nanofluid was found to be higher than its base fluid. Comparisons of convective heat transfer coefficients for Cu and Zn nanofluids with the other correlation for the nanofluids heat transfer enhancement are presented. Moreover, the flow demonstrates anomalous enhancement in heat transfer nanofluids.

Thermophysical Properties of Two-Phase Refrigerant Based Nanofluids in a Refrigeration Cycle

2016 ◽  
Author(s):  
Bilgehan Tekin ◽  
Almila G. Yazicioglu
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermophysical Properties ◽  
Base Fluid ◽  
Two Phase Flow ◽  
Cooling System ◽  
Heat Transfer Analysis ◽  
Refrigeration Cycle ◽  
Phase Flow ◽  
Two Phase

Nanofluids are a class of fluids with nanoparticles suspended in a base fluid. The aim for using nanofluids is often to improve the thermophysical properties of the base fluid so as to enhance the energy transfer efficiency. As the technology develops; the size of devices and systems needs to get smaller to fulfill the engineering requirements and/or to be leading among competitors. The use of nanofluids in heat transfer applications seems to be a viable solution to current heat transfer problems, albeit with certain limitations. As an enhancing factor for the thermal conductivity of the base fluid, nanofluids are considered to be use in cooling system applications. For these applications, the base fluid, the refrigerant, exists as a two-phase liquid-vapor mixture in parts of the refrigeration cycle. To analyze, design and optimize the cycle in such applications, the thermophysical properties of the refrigerant based nanofluids for two-phase flow of refrigerant are needed. There are different models present in the literature derived for the thermophysical properties of nanofluids. However, a majority of the existing models for nanofluid thermophysical properties have been proposed for water- and other liquids-based nanofluids, through theoretical, numerical and experimental research. Therefore, the existing models for determination of the nanofluid thermophysical properties are not applicable for refrigerant based nanofluid applications when the results are compared. Thus, in this work, a new model is derived for the thermal conductivity and viscosity of refrigerant based nanofluids, using existing data from both heat transfer and thermophysical property measurement experiments. The effect of the nanoparticles on heat transfer in two phase flow of the refrigerant is considered by applying the two phase heat transfer correlations in the literature to experimental data. As a result, the thermophysical properties of the known states are determined through known heat transfer performance. Even though the model is developed from the analysis of flow in an evaporator and flow in a single tube with evaporating refrigerant, it is aimed to cover the flows in both evaporator and condenser sections in a vapor compression refrigeration cycle to provide the necessary models for thermophysical properties in heat transfer devices which will allow the design of both cycle and evaporator or condenser in terms of sizing and rating problems by performing heat transfer analysis and/or optimization. The model can also be improved by considering the effects of slip mechanisms that lead to slip velocity between the nanoparticle and base fluid.

scholarly journals Ultrasonic and thermophysical studies of ethylene glycol nanofluids containing TiO2 nanoparticles and their heat transfer enhancements

2020 ◽  
Author(s):  
Mohit Gupta ◽  
Devraj Singh ◽  
Shakti Pratap Singh ◽  
Ashish Mathur ◽  
Shikha Wadhwa ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Tio2 Nanoparticles ◽  
Ultrasonic Velocity ◽  
Base Fluid ◽  
Sol Gel ◽  
Interaction Force ◽  
Thermal Conductivity Enhancement ◽  
Conductivity Enhancement

In present investigation, TiO2 nanostructures were synthesized via simple sol-gel technique and characterized with XRD, SEM-EDX, HRTEM and UV-visible spectroscopy techniques. The temperature and concentration dependence of thermal conductivity enhancement and ultrasonic velocity have been explored in ethylene glycol (EG)-based TiO2 nanofluids. The obtained results showed 24% enhancement in thermal conductivity at higher temperature (80°C) of base fluid ethylene glycol by adding 1.0 wt.% of TiO2 nanoparticles. The behaviour of thermal conductivity enhancement and ultrasonic velocity with temperature in prepared nanofluids has been explained with help of existing phenomena. The increase the ultrasonic velocity in ethylene glycol with TiO2 nanoparticles shows that strong cohesive interaction force rises among the nanoparticles and base fluid. These results divulge that TiO2 nanoparticles can be considered for the applications of next-generation competent heat transfer in nanofluids.

scholarly journals A REVIEW ON NANOFLUIDS: PREPARATION METHODS AND APPLICATIONS

2019 ◽  
Vol 16 (31) ◽  
pp. 365-380
Author(s):  
P. A. C. ROCHA ◽  
R. F. de M. SANTOS ◽  
R. J. P. LIMA ◽  
M. E. V. da SILVA
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermophysical Properties ◽  
Base Fluid ◽  
Solid Particles ◽  
Heat Transfer Characteristics ◽  
Preparation Methods ◽  
Automotive Electronic ◽  
New Generation ◽  
Suspended Nanoparticles

Research in heat transfer using suspensions of nanometer-sized solid particles in liquids as the base fluids have started in the last two decades. The nanofluid is a colloidal mixture composed of a base fluid and nanoparticles. The nanoparticles may be metallic, nonmetallic, ceramic, oxide and of several other categories, being the nanocomposites one of the areas of greater growth in the engineering of materials. Nanofluids are part of a new generation of high potential fluids in heat transfer applications due to their higher thermal conductivity. Most recent studies on nanofluids indicate that suspended nanoparticles markedly alter the properties and heat transfer characteristics of the suspension. This article summarizes some of the recent advances in the study of nanofluids and nanoparticles, such as their preparation methods, their thermophysical properties and finally presents various fields of applications such as solar thermal, mechanical, automotive, electronic, medical, biomedical etc.

Thermal Conductivity Enhancement by Adding Nanoparticles to Ionic Liquids

2017 ◽  
Vol 261 ◽  
pp. 121-126 ◽  
Author(s):  
Alina Adriana Minea ◽  
Madalina Georgiana Moldoveanu ◽  
Oana Dodun
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Thermophysical Properties ◽  
Base Fluid ◽  
Thermal Conductivity Enhancement ◽  
Conductivity Enhancement ◽  
New Class ◽  
Enhanced Thermal Conductivity

Ionanofluids are a very new class of nanofluids having ionic liquids as the base fluid. Thermophysical properties of base ionic liquids (ILs) and nanoparticle enhanced ionic liquids (NEILs) are part of studying a new class of fluids for heat transfer. NEILs are formed by dispersing different volume fractions of nanoparticles in a base ionic liquid. In this article, only the thermal conductivity enhancement was considered for comparison of the different ionanofluids. NEILs show enhanced thermal conductivity compared to the base ILs. Maximum thermal conductivity enhancement was observed by adding 1 % MWCNT to [C4mim][(CF3SO2)2N] ionic liquid. However, if 0.05% MWCNT are added to [(C6)3PC14)][NTf2] no enhancement in thermal conductivity was noticed.

Thermophysical Properties for ZnO-Water Nanofluid: Experimental Study

2021 ◽  
Vol 1025 ◽  
pp. 9-14
Author(s):  
Adnan H. Rasheed ◽  
Hajar Alias ◽  
Sami D. Salman
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Experimental Study ◽  
Zinc Oxide ◽  
Thermophysical Properties ◽  
Base Fluid ◽  
Volume Fraction ◽  
Nanoparticle Volume Fraction ◽  
Heat Transfer Characteristics ◽  
Rotational Viscometer

This paper presents the thermophysical properties of zinc oxide nanofluid that have been measured for experimental investigation. The main contribution of this study is to define the heat transfer characteristics of nanofluids. The measuring of these properties was carried out within a range of temperatures from 25 °C to 45 °C, volume fraction from 1 to 2 %, and the average nanoparticle diameter size is 25 nm, and the base fluid is water. The thermophysical properties, including viscosity and thermal conductivity, were measured by using Brookfield rotational Viscometer and Thermal Properties Analyzer, respectively. The result indicates that the thermophysical properties of zinc oxide nanofluid increasing with nanoparticle volume fraction increasing, as well as the thermophysical properties of zinc oxide nanofluid affected by the change in temperature.

scholarly journals Critical evaluation of nanofluids and ionanocolloids as heat transfer fluids

2021 ◽  
Vol 2116 (1) ◽  
pp. 012053
Author(s):  
Elaine Fabre ◽  
S M Sohel Murshed
Keyword(s):  
Heat Transfer ◽  
Thermophysical Properties ◽  
Base Fluid ◽  
Critical Evaluation ◽  
Heat Transfer Fluids

Abstract Nanofluids and ionanocolloids are potential heat transfer fluids with remarkable thermophysical properties. The main difference between these two types of fluids remains in the base fluid used, which significantly impacts their performances. In this work, an attempt of a critical evaluation of the most relevant characteristics of both fluids is presented and the main challenges of their application are discussed.

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