Performance Evaluation of AI2O3/Water Nanofluid as Coolant in a Double-Tube Heat Exchanger Flowing under a Turbulent Flow Regime

Navid Bozorgan,Nariman Bozorgan,Mostafa Mafi

doi:10.1155/2012/891382

Abstract

Nanofluids are expected to be a promising coolant candidate in chemical processes for water waste remediation and heat transfer system size reduction. This paper focuses on the potential mass flowrate reduction in exchanger with a given heat exchange capacity using nanofluids. Al2O3 nanoparticles with diameters of 7 nm dispersed in water with volume concentrations up to 2% are selected as a coolant, and their performance in a horizontal double-tube counterflow heat exchanger under turbulent flow conditions is numerically studied. The results show that the flowrate of nanofluid coolant decreases with the increase of concentration of nanoparticles in the exchanger with a given heat exchange capacity. The mass flowrate of the nanofluid at a volume concentration of 2 vol.% is approximately 24.5% lower than that of pure water (base fluid) for given conditions. For the pressure drop, the results show that the pressure drop of nanofluid is slightly higher than water and increases with increase of volume concentrations. In addition, the reduction of wall temperature and heat transfer area is estimated.

Highlights

Cooling is one of the top technical challenges to obtain the best heat performance in the heat exchange devices
The results indicate that the addition of nanoparticles to the base fluid enhances heat transfer performance
Results show that the heat transfer coefficient and Nusselt number can be enhanced by adding nanoparticles to the base fluid

Summary

Introduction

Cooling is one of the top technical challenges to obtain the best heat performance in the heat exchange devices. Due to the rapid development of modern technology, heat exchangers used by various industries require high heat-flux cooling to the level of tens of MW/m2. At this level, cooling with conventional fluids such as water and ethylene glycol, and so forth. Compared with traditional solid-liquid suspensions containing millimeteror micrometer-sized particles, nanofluids as coolants in the heat exchangers have shown better heat transfer performance because of the small size of suspended solid particles. It causes that nanofluids have a behavior similar to base liquid molecules

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Conclusion