Flow and Convective Heat Transfer Characteristics of Nanofluids With Various Shapes of Alumina Nanoparticles

2009 ◽  
Author(s):  
Kyo Sik Hwang ◽  
Hyo Jun Ha ◽  
Seung Hyun Lee ◽  
Hyun Jin Kim ◽  
Seok Pil Jang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Convective Heat Transfer ◽  
Flow Regime ◽  
Convective Heat ◽  
Circular Tube ◽  
Al2o3 Nanoparticles ◽  
Heat Transfer Characteristics ◽  
Laminar Flow Regime ◽  
Transfer Characteristics

This paper is to investigate flow and convective heat transfer characteristics of nanofluids with various shapes of Al2O3 nanoparticles flowing through a uniformly heated circular tube under fully developed laminar flow regime. For the purpose, Al2O3 nanofluids of 0.3 Vol.% with sphere, rod, platelet, blade and brick shapes are manufactured by a two-step method. Zeta potential as well as TEM image is experimentally obtained to examine suspension and dispersion characteristics of Al2O3 nanofluids with various shapes. To investigate flow characteristics, the pressure drop of Al2O3 nanofluids with various shapes are measured. In order to investigate convective heat transfer characteristics, the effective thermal conductivities of Al2O3 nanofluids with various shapes, the temperature distribution at the tube surface and the mean temperature of nanofluids at the inlet are measured, respectively. Based on the experimental results, the convective heat transfer coefficient of Al2O3 nanofluids with various shapes is compared with that of pure water and the thermal conductivity of Al2O3 nanofluids with various shapes. Thus, the effect of nanoparticles shape on the flow and convective heat transfer characteristics flowing through a uniformly heated circular tube under fully developed laminar flow regime is experimentally investigated.

Forced Convective Heat Transfer of Nanofluids in Microchannels

2006 ◽  
Author(s):  
Jung-Yeul Jung ◽  
Hoo-Suk Oh ◽  
Ho-Young Kwak
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Laminar Flow ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Flow Regime ◽  
Convective Heat ◽  
Volume Fraction ◽  
Convective Heat Transfer Coefficient ◽  
Laminar Flow Regime

Convective heat transfer coefficient and friction factor of a nanofluid in rectangular microchannel were measured. An integrated microsystem consisting of a single microchannel on one side and two localized heaters and five polysilicon temperature sensors along the channel on the other side were fabricated. Aluminum dioxide (Al2O3) nanofluids with various particle volume fractions were used in experiment to investigate the effect of the volume fraction of the nanoparticles to the convective heat transfer and fluid flow in microchannels. The convective heat transfer coefficient of the Al2O3 nanofluid in laminar flow regime was measured to be increased up to 15% compared to the distilled water at a volume fraction of 1.8 volume percent without major friction loss. The Nusselt number measured increases with increasing the Reynolds number in laminar flow regime. A new type of convective heat transfer correlation was proposed to correlate experimental data of heat transfer coefficient for nanofluids in microchannels.

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