Study of Convective Heat Transfer Characteristics of Nano Fluids in Circular Tube

Author(s):  
Dhirendra Patel ◽  
Anvi Sharma ◽  
Akanksha Mishra
Author(s):  
Kyo Sik Hwang ◽  
Hyo Jun Ha ◽  
Seung Hyun Lee ◽  
Hyun Jin Kim ◽  
Seok Pil Jang ◽  
...  

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.


Author(s):  
S. Kabelac ◽  
K. B. Anoop

Nanofluids are colloidal suspensions with nano-sized particles (<100nm) dispersed in a base fluid. From literature it is seen that these fluids exhibit better heat transfer characteristics. In our present work, thermal conductivity and the forced convective heat transfer coefficient of an alumina-water nanofluid is investigated. Thermal conductivity is measured by a steady state method using a Guarded Hot Plate apparatus customized for liquids. Forced convective heat transfer characteristics are evaluated with help of a test loop under constant heat flux condition. Controlled experiments under turbulent flow regime are carried out using two particle concentrations (0.5vol% and 1vol %). Experimental results show that, thermal conductivity of nanofluids increases with concentration, but the heat transfer coefficient in the turbulent regime does not exhibit any remarkable increase above measurement uncertainty.


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