Showing papers in "Experimental Thermal and Fluid Science in 2011"

TL;DR: In this article, the authors measured the forced convective heat transfer coefficient of the nanofluids using theoretical correlations in order to compare the results with the experimental data and evaluated the effects of particle concentration and operating temperature.

TL;DR: In this article, the authors investigated the macro-to-microscale transition during flow boiling in small scale channels of three different sizes with three different refrigerants over a range of saturation conditions to investigate the effects of channel confinement on two-phase flow patterns and liquid film stratification.

TL;DR: In this paper, five different carbon nanotube (CNT) structures, namely SWNTs, DWNTs (double wall CNT), FWNTs and two different MWNTs were synthesized to prepare nanofluids with three different dispersion methods.

TL;DR: In this article, the authors investigated the effects of channel confinement, heat flux, flow pattern, saturation temperature, subcooling and working fluid properties on the two-phase heat transfer and CHF.

TL;DR: In this article, the authors compare experimentally the thermal performances of two types of commercial nanofluids, composed of oxides of alumina (γAl 2 O 3 ) dispersed in water and aqueous suspensions of nanotubes of carbons (CNTs).

TL;DR: In this paper, the effects of tunnel blockage on the turbine power coefficient in wind tunnel tests of small horizontal-axis wind turbines were quantitatively investigated by measuring the tunnel velocities with and without rotors using a pitot-static tube under various test conditions.

TL;DR: In this paper, an experimental investigation on the convective heat transfer and friction factor characteristics in the plain and dimpled tube under laminar flow with constant heat flux is carried out with distilled water and CuO/water nanofluids.

TL;DR: In this paper, an infrared camera coupled with a microscopic lens giving a spatial resolution of 10 μm was used to observe the evaporation of sessile drops in infrared wavelengths, including ethanol, methanol and FC-72.

TL;DR: In this article, the application of nanofluids as the working fluid on a heat pipe liquid-block combined with thermoelectric cooling is investigated, and the results obtained from this technique are compared to those from other conventional cooling techniques.

TL;DR: In this paper, the effect of surfactant additives on nucleate pool boiling heat transfer of refrigerant-based nanofluid was investigated experimentally, and the experimental results indicate that the presence of a surfactants enhances the nucleate-pool boiling transfer on most conditions, but deteriorates the nucleates pool boiling transfer at high surfactan concentrations.

TL;DR: In this article, experimental condensation heat transfer data for the new refrigerant R1234ze(E), trans-1, 3,3,3-3-tetrafluoropropene, are presented and compared with refrigerants R134a and R236fa for a vertically aligned, aluminum multi-port tube.

TL;DR: In this article, a rectangular duct roughened with W-shaped ribs arranged at an inclination with respect to the flow direction on its underside on one broad wall has been tested.

TL;DR: In this paper, the heat transfer characteristics of two-phase closed thermosyphon (TPCT) with iron oxide-nanofluids are presented, which is fabricated from the copper tube with the outer diameter and length of 15, 2000 mm, respectively.

TL;DR: In this article, a detailed map of the flow sub-regimes in a shear-driven liquid film flow of water and FC-72 have been obtained for a 2-mm channel operating at room temperature.

TL;DR: In this paper, a flat-plate oscillating heat pipe (FP-OHP) with Tesla-type check valves was integrated into a flatplate OHP in order to promote and sustain a desired circulatory flow to increase overall thermal performance.

TL;DR: In this paper, the effect of Al 2 O 3 particles on the heat transfer performance of an oscillating heat pipe (OHP) was investigated experimentally, and it was found that all particles added in the OHP can improve the startup performance.

TL;DR: In this paper, the effect of rounding of the sharp edges at the impeller periphery (or turbine inlet) has shown tendencies of performance enhancement in pump as turbine applications, and the authors concluded that the effect is very important for performance optimization and recommends its application on all pump as turbines projects.

TL;DR: In this paper, the free-surface fluctuations and air-water properties of the hydraulic jump roller were investigated physically for relatively small Froude numbers (2.4 < Fr-1 < 5.1) and relatively large Reynolds numbers (6.6 x 10(4) < Re < 1.3x 10(5)).

TL;DR: In this article, the surface wettability is a critical parameter in small scale phenomena, especially two-phase flow, since the surface force becomes dominant as size decreases, and visualization of flow patterns was carried out.

TL;DR: In this article, the authors measured the heat transfer coefficients of CO 2 in a single microchannel in a horizontal stainless steel tube of 0.529mm inner diameter, for three temperatures (−10, −5 and 0,°C), with the mass flux ranging from 200 to 1200 kg/m 2 ǫs and the heat flux varying from 10 to 30 kW/m2.

TL;DR: In this article, the authors present the measurement of the thermal conductivity and the dynamic viscosity of Al2O3-water and TiO2-water nano-fluids carried out at atmospheric pressure in the temperature range from 1 to 40°C.

TL;DR: In this article, the volume fraction dependence of the thermal conductivity enhancement at room temperature is predicted fairly well considering contributions from both nanolayer at the solid-liquid interface and particle agglomeration in the suspension, as visualized by Feng et al.

TL;DR: Forced convection heat transfer of non-Newtonian nanofluids in a circular tube with constant wall temperature under turbulent flow conditions was investigated experimentally in this article.

TL;DR: In this article, three types of diverging microchannels (Type 1, Type 2 and Type 3) were designed to experimentally investigate the effect of different distributions of artificial nucleation sites (ANS) on the enhancement of flow boiling heat transfer.

TL;DR: In this paper, an experimental study of heat transfer during quenching of a cylindrical stainless steel test specimen has been performed, where a subcooled water jet is directed onto the upward facing flat face of the cylinder.

TL;DR: In this article, the effects of nanostructured surface coatings on boiling heat transfer and critical heat flux were studied on a 100-μm diameter platinum wire immersed in saturated water or pentane at 1 bar.

TL;DR: In this article, the authors investigated the effects of inlet and outlet locations in a search for an optimum configuration in a parallel flow heat exchanger with two pass configuration and found that significant liquid flows through bottom channels, and less liquid is supplied to top channels.

TL;DR: In this paper, the effects of radial fin and turbulence promoters on the enhancement of phase change heat transfer external to a horizontal tube submersed in the PCM with the working fluid flowing through it were investigated.

TL;DR: In this article, the effects of pressure, inner wall heat flux and mass flux on heat transfer characteristics are analyzed, the heat transfer mechanism and the frictional resistance performance are discussed, and corresponding empirical correlations are presented.

TL;DR: In this article, the authors presented the flow boiling heat transfer characteristics of R134a in the multiport minichannel heat exchanger and compared the results of two test sections with different the number of channels.