APPARATUS DESIGN FOR MEASURING FORCED CONVECTION HEAT TRANSFER COEFFICIENTS OF SUPERCRITICAL H2O/CO2 MIXTURES

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.

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

Volume 9: Micro- and Nano-Systems Engineering and Packaging, Parts A and B ◽

10.1115/imece2012-89962 ◽

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.

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Forced Convection Heat Transfer From a Uniformly Heated Cylinder

Journal of Heat Transfer ◽

10.1115/1.3684359 ◽

1962 ◽

Vol 84 (3) ◽

pp. 257-261 ◽

Cited By ~ 40

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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