scholarly journals Base fluid and temperature effects on the heat transfer characteristics of SiC in ethylene glycol/H2O and H2O nanofluids

2011 ◽  
Vol 109 (1) ◽  
pp. 014914 ◽  
Author(s):  
Elena V. Timofeeva ◽  
Wenhua Yu ◽  
David M. France ◽  
Dileep Singh ◽  
Jules L. Routbort
Keyword(s):  
Heat Transfer ◽  
Ethylene Glycol ◽  
Temperature Effects ◽  
Base Fluid ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

scholarly journals Conduction and convection heat transfer characteristics of water-based au nanofluids in a square cavity with differentially heated side walls subjected to constant temperatures

2014 ◽  
Vol 18 (suppl.1) ◽  
pp. 189-200 ◽  
Author(s):  
Primoz Ternik ◽  
Rebeka Rudolf
Keyword(s):  
Heat Transfer ◽  
Rayleigh Number ◽  
Base Fluid ◽  
Volume Fraction ◽  
Heat Transfer Characteristics ◽  
Square Cavity ◽  
Onset Of Convection ◽  
Transfer Characteristics ◽  
Wide Range ◽  
Water Based

The present work deals with the natural convection in a square cavity filled with the water-based Au nanofluid. The cavity is heated on the vertical and cooled from the adjacent wall, while the other two horizontal walls are adiabatic. The governing differential equations have been solved by the standard finite volume method and the hydrodynamic and thermal fields were coupled together using the Boussinesq approximation. The main objective of this study is to investigate the influence of the nanoparticles? volume fraction on the heat transfer characteristics of Au nanofluids at the given base fluid?s (i.e. water) Rayleigh number. Accurate results are presented over a wide range of the base fluid Rayleigh number and the volume fraction of Au nanoparticles. It is shown that adding nanoparticles in a base fluid delays the onset of convection. Contrary to what is argued by many authors, we show by numerical simulations that the use of nanofluids can reduce the heat transfer rate instead of increasing it.

Two-Phase Analysis on the Conjugate Heat Transfer Performance of Microchannel With Cu, Al, SWCNT, and Hybrid Nanofluids

2017 ◽  
Vol 9 (4) ◽  
Author(s):  
Rajesh Nimmagadda ◽  
K. Venkatasubbaiah
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Base Fluid ◽  
Average Nusselt Number ◽  
Conjugate Heat Transfer ◽  
Pure Water ◽  
Heat Transfer Characteristics ◽  
Two Phase ◽  
Transfer Characteristics ◽  
Hybrid Nanofluids

This numerical study has been carried out by developing two-phase mixture model with conjugate heat transfer. Pure and hybrid nanofluids (HyNF) with particle as well as base fluid hybridization are used in analyzing the performance of microchannel under forced convection laminar flow. The flow as well as heat transfer characteristics of pure water, copper (Cu), aluminum (Al), single-walled carbon nanotube (SWCNT), and hybrid (Cu + Al, water + methanol) nanofluids with various nanoparticle volume concentrations at different Reynolds numbers are reported. Sphericity-based effective thermal conductivity evaluation is considered in the case of SWCNT nanofluids by using volume and surface area of nanotubes. A significant enhancement in the average Nusselt number is observed numerically for both pure and hybrid nanofluids. Pure nanofluids such as Al, Cu, and SWCNT with 3 vol % nanoparticle concentration enhanced the average Nusselt number by 21.09%, 32.46%, and 71.25% in comparison with pure water at Re = 600. Whereas, in the case of hybrid nanofluids such as 3 vol % HyNF (0.6% Cu + 2.4% Al) and 3 vol % SWCNT (20% Me + 80% PW), the enhancement in average Nusselt number is observed to be 23.38% and 46.43% in comparison with pure water at Re = 600. The study presents three equivalent combinations of nanofluids (1 vol % Cu and 0.5 vol % SWCNT), (2 vol % Cu, 1 vol % SWCNT and 3 vol % HyNF (0.6% Cu + 2.4% Al)) as well as (2 vol % SWCNT and 3 vol % SWCNT (20% Me + 80% PW)) that provides a better switching option in choosing efficient working fluid with minimum cost based on cooling requirement. The study also shows that by dispersing SWCNT nanoparticles, one can enhance the heat transfer characteristics of base fluid containing methanol as antifreeze. The conduction phenomena of solid region cause the interface temperature between solid as well as fluid regions to increase along the length of the microchannel. The developed numerical model is validated with the numerical and experimental results available in the literature.

scholarly journals Hydromagnetic Boundary Layer Flow and Heat Transfer Characteristics of a Nanofluid over an Inclined Stretching Surface in the Presence of a Convective Surface: A Comprehensive Study

2015 ◽  
Vol 19 (2) ◽  
pp. 53 ◽  
Author(s):  
Mohammad M. Rahman ◽  
Mohammed M. Al-Hatmi
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Differential Equations ◽  
Boundary Layer Flow ◽  
Base Fluid ◽  
Stretching Surface ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Layer Flow

In this paper we investigate numerically the hydromagnetic boundary layer flow and heat transfer characteristics of a nanofluid using three types of nanoparticles (copper, aluminium oxide and titanium dioxide) having various shapes (spherical, cylindrical, arbitrary, etc) by considering three kinds of base fluids (water, ethylene glycol and engine oil) over a nonlinear inclined stretching surface, taking into account the effect of convective surface condition. Using similarity transformations, the governing nonlinear partial differential equations of the physical model are transformed into non-dimensional ordinary differential equations which are solved for local similar solutions using the very robust computer algebra software, Maple 13. The numerical simulation is carried out to investigate the role of the pertinent parameters on the flow and temperature fields as well as on the rate of heat transfer and on the rate of shear stress. The results show that the addition of nanoparticles to the base fluid may not always increase the rate of heat transfer. It depends significantly on the surface convection, type of base fluid and nanoparticles.  The finding of this study will open a gate for better understanding of nanofluid characteristics.  

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