Convective Heat Transfer and Fluid Dynamic Characteristics of SiO2 Ethylene Glycol/Water Nanofluid

2008 ◽  
Vol 29 (12) ◽  
pp. 1027-1035 ◽  
Author(s):  
Devdatta P. Kulkarni ◽  
Praveen K. Namburu ◽  
H. Ed Bargar ◽  
Debendra K. Das
Keyword(s):  
Heat Transfer ◽  
Ethylene Glycol ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Dynamic Characteristics ◽  
Fluid Dynamic

scholarly journals Effect of Magnetic Field on the Forced Convective Heat Transfer of Water–Ethylene Glycol-Based Fe3O4 and Fe3O4–MWCNT Nanofluids

2021 ◽  
Vol 11 (10) ◽  
pp. 4683
Author(s):  
Areum Lee ◽  
Chinnasamy Veerakumar ◽  
Honghyun Cho
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Field Strength ◽  
Ethylene Glycol ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Hybrid Nanofluid ◽  
Forced Convective Heat Transfer ◽  
The Magnetic Field

This paper discusses the forced convective heat transfer characteristics of water–ethylene glycol (EG)-based Fe3O4 nanofluid and Fe3O4–MWCNT hybrid nanofluid under the effect of a magnetic field. The results indicated that the convective heat transfer coefficient of magnetic nanofluids increased with an increase in the strength of the magnetic field. When the magnetic field strength was varied from 0 to 750 G, the maximum convective heat transfer coefficients were observed for the 0.2 wt% Fe3O4 and 0.1 wt% Fe3O4–MWNCT nanofluids, and the improvements were approximately 2.78% and 3.23%, respectively. The average pressure drops for 0.2 wt% Fe3O4 and 0.2 wt% Fe3O4–MWNCT nanofluids increased by about 4.73% and 5.23%, respectively. Owing to the extensive aggregation of nanoparticles by the external magnetic field, the heat transfer coefficient of the 0.1 wt% Fe3O4–MWNCT hybrid nanofluid was 5% higher than that of the 0.2 wt% Fe3O4 nanofluid. Therefore, the convective heat transfer can be enhanced by the dispersion stability of the nanoparticles and optimization of the magnetic field strength.

Enhanced Natural Convective Heat Transfer of CNT-Ethylene Glycol-Water Suspensions

2008 ◽  
Author(s):  
Sanjeeva Witharana ◽  
Haisheng Cheng ◽  
Yulong Ding
Keyword(s):  
Heat Transfer ◽  
Ethylene Glycol ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Cylindrical Cavity ◽  
Vertical Axis ◽  
Axis Orientation ◽  
Horizontal Orientation ◽  
Water Suspensions ◽  
Base Liquid

This paper presents an experimental study on the rheology and steady state natural convective heat transfer of suspensions of Carbon nanotubes (CNT) in the Water - Ethylene Glycol (WEG) base liquid, heated in a cylindrical cavity. Two series of experiment were performed in two orientations of the central axis of the cavity; vertical, and, horizontal. In vertical axis experiments, the heat was supplied from the bottom. The cylindrical cavity was made out of Aluminium, 10mm in height and 240mm in diameter. The heat input was 215W/m2. The CNTs used had an aspect ratio of ∼150. There were six suspensions investigated in either series of tests; CNT 0.1wt%, and EG 0, 10, 25, 50, 75 & 100wt%. It was found that the vertical axis orientation deteriorates heat transfer in all cases. However for horizontal orientation, there is a spectacular enhancement of up to 83% depending upon the EG concentration. The results also show that WEG-CNT suspension demonstrates non-Newtonian behaviour, which augments with increasing EG concentration.

Evaluating the Effect of Number of Spans on Heat Transfer in Greenhouses

2019 ◽  
Author(s):  
S. Kruger ◽  
L. Pretorius
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Fluid Dynamic ◽  
Cfd Model ◽  
Transfer Velocity ◽  
Nusselt Number Distribution ◽  
Convective Cells ◽  
Rayleigh Benard Convection ◽  
Rayleigh Benard

Abstract The present study concerns convective flows in the empty volume above the plant canopy in a confined greenhouse. The purpose of this paper is to numerically investigate the effect of the number of spans on the convective heat transfer in closed greenhouses. The initial greenhouse CFD model cavity is validated against experimental results found in the literature. Thermal convection is induced by heating the bottom of the cavity. The numerical model is then modified to represent two-l greenhouse cavities with different numbers of spans. The computational fluid dynamic (CFD) software is then used to analyze mainly the natural convective heat transfer, velocity and temperature distributions for the single span greenhouse, as well as multi-span greenhouses (containing two and three spans). The greenhouse CFD model floor is heated, and the walls are adiabatic, corresponding to Rayleigh-Bénard convection. A mesh sensitivity analysis was conducted to determine a suitable size for the mesh. Results show that adding additional spans to the initial single-span cavity has a pronounced effect on the Nusselt-number distribution on the floor of the cavity. The temperature and velocity distributions were also significantly influenced. The four-span cavity showed three convective cells instead of four as for the lowest Rayleigh number.

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