Numerical study of fluid flow and convective heat transfer characteristics in a sinusoidal wavy circular tube

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.

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A Numerical Study on the Convective Heat Transfer Characteristics of Pulsed Impingement Drying

Drying Technology ◽

10.1080/07373937.2012.683121 ◽

2012 ◽

Vol 30 (10) ◽

pp. 1056-1061 ◽

Cited By ~ 16

Author(s):

Ying Jiang ◽

Peng Xu ◽

Arun S. Mujumdar ◽

Shuxia Qiu ◽

Zhouting Jiang

Keyword(s):

Heat Transfer ◽

Convective Heat Transfer ◽

Convective Heat ◽

Numerical Study ◽

Heat Transfer Characteristics ◽

Transfer Characteristics

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Convective heat transfer characteristics of microalgae slurries in a circular tube flow

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2019.03.166 ◽

2019 ◽

Vol 137 ◽

pp. 823-834 ◽

Cited By ~ 8

Author(s):

Hao Chen ◽

Qiang Liao ◽

Qian Fu ◽

Yun Huang ◽

Ao Xia ◽

...

Keyword(s):

Heat Transfer ◽

Convective Heat Transfer ◽

Convective Heat ◽

Circular Tube ◽

Tube Flow ◽

Heat Transfer Characteristics ◽

Transfer Characteristics

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Numerical Study on Supercritical CH4/N2 Cooling in a Horizontal Tube

Volume 2: Heat Transfer Enhancement for Practical Applications; Fire and Combustion; Multi-Phase Systems; Heat Transfer in Electronic Equipment; Low Temperature Heat Transfer; Computational Heat Transfer ◽

10.1115/ht2012-58259 ◽

2012 ◽

Author(s):

Zhongxuan Du ◽

Wensheng Lin ◽

Anzhong Gu

Keyword(s):

Heat Transfer ◽

Nitrogen Content ◽

Convective Heat Transfer ◽

Convective Heat ◽

Numerical Study ◽

Horizontal Tube ◽

Buoyancy Effect ◽

Heat Transfer Characteristics ◽

Bottom Line ◽

Transfer Characteristics

Coalbed methane (CBM) is a kind of mixed gas with the principal component of methane and nitrogen. Supercritical convective heat transfer of CH4/N2 cooled in horizontal circular tubes is one of the most important heat transfer processes during CBM liquefaction. In this paper, supercritical CH4/N2 cooling has been numerically investigated in a horizontal tube by using the low Reynolds number turbulence model proposed by Lam and Bremhorst. The study first focuses on the effect of nitrogen content on CBM heat transfer characteristics. The results indicate that supercritical convective heat transfer of CBM is mainly affected by the fact that the CBM properties change with nitrogen content. Then the study focuses on the buoyancy effect on heat transfer characteristics at different mass fluxes, heat fluxes and pressures. The results show that buoyancy effect increases with the decrease of mass flux or with the increase of heat flux, and the relationship Gr/Re2.7 predicts the buoyancy effect onset better than Gr/Re2. When the buoyancy effect is considerably strong, buoyancy effect on heat transfer in the top line of the horizontal circular tube is equivalent to buoyancy-opposed heat transfer, and buoyancy effect on heat transfer in the bottom line to buoyancy-aided heat transfer. The correlation of buoyancy-opposed heat transfer proposed by Bruch et al. predicts well for the supercritical heat transfer of methane. When the buoyancy effect is negligible, the calculated results agree well with the Gnielinski correlation.

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