Local convective heat transfer from a horizontal tube in an acoustic cavitation field

2004 ◽  
Vol 13 (4) ◽  
pp. 338-343 ◽  
Author(s):  
Dingwei Zhou ◽  
Xuegong Hu ◽  
Dengying Liu
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Horizontal Tube ◽  
Acoustic Cavitation ◽  
Cavitation Field

Some aspects of free-convective heat transfer in eddy flow through a horizontal tube

1993 ◽  
Vol 36 (18) ◽  
pp. 4487-4491 ◽  
Author(s):  
V.F. Vinokurov ◽  
S.V. Volkov ◽  
O.G. Martynenko ◽  
P.P. Khramtsov ◽  
I.A. Shikh
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Horizontal Tube ◽  
Flow Through ◽  
Eddy Flow ◽  
Free Convective Heat Transfer

scholarly journals Experimental Study on the Flow and Heat Transfer of Graphene-Based Lubricants in a Horizontal Tube

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1675
Author(s):  
Zhongpan Cai ◽  
Maocheng Tian ◽  
Guanmin Zhang
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Horizontal Tube ◽  
Lubricating Oil ◽  
Heat Transfer Characteristics ◽  
Experiment Platform ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer

To improve the heat transfer characteristics of lubricant, graphene-based lubricants were prepared by adding graphene particles, due to its advantages of excellent thermal conductivity and two-dimensional sheet structure. In the present study, its physical properties were measured. A flow heat transfer experiment platform was built to study the flow and heat transfer characteristics of the graphene lubricating oil in a horizontal circular tube. The results show that the graphene lubricant prepared using a two-step approach had good stability, and the dispersibility was good without the agglomeration phenomenon, according to measurements undertaken using an electron microscope and centrifuge. The thermal conductivity and viscosity of graphene lubricant increased with the increase of the graphene concentration, and the thermal conductivity of graphene lubricant with the same concentration decreased with the increase of temperature. When the concentration was equal, the convective heat transfer Nusselt number (Nu) of graphene lubricant increased with the increase of Reynolds number (Re). When Re was equal, the convective heat transfer Nu increased with the increase of graphene particle concentration, and the maximum Nu increased by 40%.

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

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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