Characterizations of Nanofluid Heat Transfer Enhancements
Final rept. Aug 2010-Jul 2013
TEXAS UNIV AT SAN ANTONIO
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Nanoparticle morphology is thought to be an important factor influencing heat and mass transfer rates in liquid systems. How nanoparticles mechanistically increase heat and mass transfer rates is not well understood. Both dispersed nanoparticles and aggregated nanoparticles are thought to play important roles. Dispersed nanoparticles and associated nanoparticle Brownian movements are purported to cause the enhancements by mixing mechanisms whereas aggregated nanoparticles are purported to cause enhancements by forming highly conductive paths. In this study, morphologies of nanoparticle were quantified in laboratory studies and related to laboratory measured heat and mass transfer rates. No mass transfer enhancements were found in the presence of nanoparticles. Thermal conductivity could be predicted with effective medium theory when aggregated nanoparticle aspect ratio was considered.