Thermal Conductivity of Al2O3 and CeO2 Nanoparticles and Their Hybrid Based Water Nanofluids: An Experimental Study

Mohammed Saad Kamel,Ferenc Lezsovits,Otabeh Al-Oran

doi:10.3311/ppch.15382

Abstract

In many heat exchange systems, there is a demand to improve the thermal conductivity of the working fluids to make those fluids more efficient, and this can be done by dispersing solid nanomaterials into conventional liquids. In the present work, the thermal conductivity of alumina, ceria, and their hybrid with ratio (50:50) by volume-based deionized water nanofluids was experimentally measured. The nanofluids were prepared by two-step method with a range of dilute volume concentration (0.01-0.5 % Vol.), and measured at various temperatures (35, 40, 45, and 50 ºC). The experimental data for basefluid and nanofluids were verified with theoretical and experimental models, and the results have shown good agreement within the accuracy of the thermal conductivity tester. The results demonstrated that the higher thermal conductivity enhancement percentages for Al2O3, CeO2, and their hybrid nanofluids were (5.3 %, 3.3 %, and 8.8 %) at volume concentration (0.5 % Vol.) and temperature (50 ºC) compared to deionized water, respectively. Moreover, a correlation was proposed for the thermal conductivity enhancement ratio of the hybrid nanofluid and showed good accuracy with measured experimental data.

Highlights

Conventional fluids thermal properties have been modified by dispersing ultrafine solid particles within a range of 1-100 nm, which are consist of metallic or non-metallic nanoparticles as well as carbon nanotubes to produce new thermal fluids so-called nanofluids [1,2,3]
3 Results and discussion 3.1 Thermal conductivity of Al2O3 based deionized water nanofluid Thermal conductivity of alumina nanoparticles based deionized water nanofluids was measured at various temperatures (35-50 °C), and different dilute volume concentration (0.01 % - 0.5 %)
The results demonstrated that the temperature has more effect than the volume concentration on thermal conductivity enhancement ratio, and this could be attributed to the increase in the Brownian motion of the nanoparticles during the higher temperature [1, 44]

Summary

Introduction

Conventional fluids thermal properties have been modified by dispersing ultrafine solid particles within a range of 1-100 nm, which are consist of metallic or non-metallic nanoparticles as well as carbon nanotubes to produce new thermal fluids so-called nanofluids [1,2,3]. Thermal conductivity is an important thermal transport property to which the applicability of using the nanofluids is attributed as it influences the heat transfer performance. This property considered as a major key to enhancing the nanofluids heat transfer performance in many heat exchange systems, which are included the boiling process [4,5,6], cooling of electronic devices [7, 8], solar energy [9], geothermal energy [10], etc. Enhancement of the thermal conductivity of the working fluids could offer a good opportunity to increase the heat transfer rate, which, in turn, improves the thermal efficiency of the heat exchange systems. Thermal conductivity enhancement was reported from the literature by using several types of nanomaterials based on different types of basefluids such as Al2O3 [21], TiO2 [22], MgO [23], MWCNT [24], ZnO, CuO, and SiO2 [25, 26]

Objectives

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Results

Conclusion