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Author(s): , , , , , ,

Keywords: , , , , , , , ,

Abstract: Nanofluids are relatively new materials that are composed of liquids containing solid nanoparticles ranging from 1-100 nm. This study examined the thermal conductivity of Al2O3 (aluminum oxide)-H2O nanofluids in water under multiple pH and sodium dodecylbenzenesulfonate (SDBS) conditions. A hot disk transient plane source (TPS) was used to measure the thermal conductivities of the samples. It was found that when the pH of the nanofluid reached approximately 8.0, the solution moved away from the point of zero change (PZC) and the thermal conductivity of the solution increased. The PZC is the pH value where the nanofluid particles aggregate; when this state is disturbed, the particles spread out and heat can more efficiently pass through the sites on their surfaces. It was also discovered that the nanofluid became stabilized at a higher concentration of SDBS than the concentration where thermal conductivity was optimized.  Therefore, particle stability is compromised when thermal conductivity is highest. 

Reference: Current Applied Physics, 9 (2009) 131-139

DOI: 10.1016/j.cap.2007.12.008