Experimental Heat Transfer 

About: Experimental Heat Transfer is an academic journal published by Taylor & Francis. The journal publishes majorly in the area(s): Heat transfer & Heat transfer coefficient. It has an ISSN identifier of 0891-6152. Over the lifetime, 990 publications have been published receiving 17632 citations.

Hydrodynamic and heat transfer study of dispersed fluids with submicron metallic oxide particles

Abstract: Turbulent friction and heat transfer behaviors of dispersed fluids (i.e., uttrafine metallic oxide particles suspended in water) in a circular pipe were investigated experimentally. Viscosity measurements were also conducted using a Brookfield rotating viscometer. Two different metallic oxide particles, γ-alumina (Al2O3) and titanium dioxide (TiO2), with mean diameters of 13 and 27 nm, respectively, were used as suspended particles. The Reynolds and Prandtl numbers varied in the ranges l04-I05 and 6.5-12.3, respectively. The viscosities of the dispersed fluids with γ-Al2O3 and TiO2 particles at a 10% volume concentration were approximately 200 and 3 times greater than that of water, respectively. These viscosity results were significantly larger than the predictions from the classical theory of suspension rheology. Darcy friction factors for the dispersed fluids of the volume concentration ranging from 1% to 3% coincided well with Kays' correlation for turbulent flow of a single-phase fluid. The Nusselt n...

Estimation of Thermal Conductivity of Nanofluid Using Experimental Effective Particle Volume

Abstract: The thermal conductivities of nanofluid containing a small amount of ultra-dispersed diamond (UDD), silver, and silica nanoparticles were measured using a transient hot-wire method. To explain the enhancement of thermal conductivity of nanofluid, the effective volume of nanoparticles was used instead of the real volume to predict the thermal conductivity of nanofluid. The liquid layering on the surface of nanoparticles may be described as the effective volume of nanoparticles. This liquid layering is one important mechanism of the heat transfer in nanofluids. The effective volume of nanoparticles was estimated from high shear viscosity of nanofluid using the Einstein equation. The Hamilton–Crosser model with an effective volume fraction of nanoparticles resulted in better correlation for the thermal conductivities of nanofluids.

Frictional flow characteristics of water flowing through rectangular microchannels

Abstract: Experiments were conducted to investigate the flow characteristics of water flowing through rectangular microchannels having hydraulic diameters of 0.133-0.367 mm and H/W ratios of 0.333-1. Experimental results indicated that the laminar flow transition occurred at Reynolds numbers of 200-700. This critical Re for the laminar transition was strongly affected by the hydraulic diameter, decreasing with corresponding decreases in the microchannel. In addition, the size of the transition range was diminished and fully developed turbulent flow also occurred at much lower Re. The friction behavior of both the laminar and turbulent flow was found to depart from the classical thermqfluid correlations. lite friction factor, f, was found to be proportional to Re−1.98 rather than Re for the laminar condition, and proportional to Re−1.72i for turbulent flow. The geometric parameters, hydraulic diameter, and H/W were found to be the most important parameters and had a critical effect on the flow. Generally, increasing...

Experimental Investigation on the Thermal Conductivity and Viscosity of Silver-Deionized Water Nanofluid

Abstract: This article presents an experimental investigation where the thermal conductivity and viscosity of silver-deionized water nanofluid is measured and studied. The mixture consists of silver nanoparticles of 0.3, 0.6, and 0.9% of volume concentrations and studied for temperatures between 50°C and 90°C. The transient hot-wire apparatus and Cannon-Fenske viscometer are used to measure the thermal conductivity and kinematic viscosity of nanofluid, respectively. The thermal conductivity increases with the increase in temperature and particle concentrations. A minimum and maximum enhancement of 27% at 0.3 vol% and 80% at 0.9 vol% are observed at an average temperature of 70°C. The viscosity decreases with the increase in temperature and increases with the increase in particle concentrations. The effect of Brownian motion and thermophoresis on the thermo-physical properties is discussed. Thus, an experimental correlation for thermal conductivity and viscosity, which relates the volume concentration and t...

Heat transfer characteristics of water flowing through microchannels

Abstract: The forced-flow convection of water through rectangular microchannels having hydraulic diameters of 0.133-0.367 mm and aspect ratios of H/W = 0.333-1 was investigated experimentally. The flow friction was measured to analyze the heat transfer regimes and to explore the physical aspects of the connective heat transfer. The experimental measurements indicated that the upper bound of the laminar heat transfer regime occurred at a Reynolds number of 200-700, and fully turbulent connective heat transfer was reached at Reynolds numbers of 400-1,500. The transition Reynolds number diminished with the reduction of the microchannel dimension, and the transition range was observed to become smaller in magnitude. For the laminar heat transfer regime, the Nusselt number was found to be proportional to Re0.62while the turbulent heat transfer case exhibited a typical relationship between Nu and Re, but with a different empirical coefficient, CH,t. The geometric parameters were found to be important variables that could...