Numerical Simulation of Laminar Forced Convection Heat Transfer of Two Square Prisms Inside Nanofluids

2012 ◽  
Author(s):  
S. M. H. Jayhooni ◽  
M. H. Nowzari ◽  
K. Jafarpur ◽  
A. Abbasi Baharanchi
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Base Fluid ◽  
Convection Heat Transfer ◽  
Particle Diameter ◽  
Convection Heat ◽  
Transfer Coefficients ◽  
Volumetric Concentration ◽  
Forced Convection Heat Transfer ◽  
High Particle

Forced convection heat transfer for steady free stream flow past two isothermal prisms inside different nanofluids has been studied numerically. Nanofluids have been consisted of Al2O3 and CuO nanoparticles with different particle diameters (dnp = 30nm and 100nm) and different particle volumetric concentrations (0% < φ < 4%). Besides, water is used as base fluid for all nanofluids. In this research the recent correlations are used for viscosity and thermal conductivity of nanofluids. The correlations are function of temperature and particle volumetric concentration. The present numerical simulations have been performed for Pe < 200 in which the flow is steady and laminar. The results show that the heat transfer coefficients for all nanofluids are higher than the base fluid (water). These enhancements are more considerable in high Peclet numbers and high particle volumetric concentrations. In addition, among the tested nanofluids, the CuO/water with 4% particle volumetric concentration and 100nm particle diameter finds to be the best nanofluid to increase the heat transfer. The effect of nanofluids on increasing heat transfer is lower for second prism as compared with the first one.

An Experimental Investigation on Forced Convection Heat Transfer From a Cylinder Embedded in a Packed Bed

1994 ◽  
Vol 116 (1) ◽  
pp. 73-80 ◽  
Author(s):  
K. Nasr ◽  
S. Ramadhyani ◽  
R. Viskanta
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Forced Convection ◽  
Convection Heat Transfer ◽  
Particle Diameter ◽  
Packed Bed ◽  
Spherical Particles ◽  
Theoretical Equation ◽  
Convection Heat ◽  
Forced Convection Heat Transfer

Forced convection heat transfer from a cylinder embedded in a packed bed of spherical particles was studied experimentally. With air as the working fluid, the effects of particle diameter and particle thermal conductivity were examined for a wide range of thermal conductivities (from 200 W/m K for aluminum to 0.23 W/m K for nylon) and three nominal particle sizes (3 mm, 6 mm, and 13 mm). In the presence of particles, the measured convective heat transfer coefficient was up to seven times higher than that for a bare tube in crossflow. It was found that higher heat transfer coefficients were obtained with smaller particles and higher thermal conductivity packing materials. The experimental data were compared against the predictions of a theory based on Darcy’s law and the boundary layer approximations. While the theoretical equation was moderately successful at predicting the data, improved correlating equations were developed by modifying the form of the theoretical equation to account better for particle diameter and conductivity variations.

Transient Forced Convection Heat Transfer to Helium During a Step in Heat Flux

1983 ◽  
Vol 105 (2) ◽  
pp. 350-357 ◽  
Author(s):  
P. J. Giarratano ◽  
W. G. Steward
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Forced Convection ◽  
Carbon Film ◽  
Convection Heat Transfer ◽  
Fast Response ◽  
Operating Conditions ◽  
Convection Heat ◽  
Transfer Coefficients ◽  
Forced Convection Heat Transfer

Transient forced convection heat transfer coefficients for both subcritical and supercritical helium in a rectangular flow channel heated on one side were measured during the application of a step in heat flux. Zero flow data were also obtained. The heater surface which served simultaneously as a thermometer was a fast response carbon film. Operating conditions covered the following range: Pressure, 1.0 × 105 Pa (1 bar) to 1.0 × 106 Pa (10 bar); Temperature, 4 K–10 K; Heat Flux, 0.1 W/cm2−10 W/cm2; Reynolds number, 0–8 × 105. The experimental data and a predictive correlation are presented.

Forced Convection Heat Transfer From a Uniformly Heated Cylinder

1962 ◽  
Vol 84 (3) ◽  
pp. 257-261 ◽  
Author(s):  
H. C. Perkins ◽  
G. Leppert
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Convection Heat Transfer ◽  
Practical Interest ◽  
Reynolds Numbers ◽  
Convection Heat ◽  
Transfer Coefficients ◽  
Heated Cylinder ◽  
Forced Convection Heat Transfer ◽  
Prandtl Numbers

Forced convection heat transfer from a cylindrical heating element with crossflow occurs in many situations of practical interest, but heat-transfer coefficients for liquids have been reported in the literature only for Reynolds numbers below 200. This paper correlates new data taken with water and ethylene glycol at Reynolds numbers from 40 to 100,000 and Prandtl numbers from 1 to 300. The effects of temperature differences large enough to produce significant changes in viscosity across the boundary layer have also been investigated and are correlated in terms of a viscosity ratio.

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