Forced-convection boiling experiments were performed with FC-72, a 3M Fluorinert, at 1.36 bar on a linear array of nine discrete heat sources simulating microelectronic chips, which were flushmounted in a vertical. rectangular channel. The inlet velocity and liquid subcooling were varied from 13 to 400 cm s’ and 3 to 36”C, respectively. Special design of the experimental apparatus allowed each ...

The effects on pool boiling characteristics such as critical heat flux and the heat transfer coefficient of different surface characteristics such as surface wettability, roughness, morphology, and porosity are not well understood. Layer-by-layer nanoparticle coatings were used to modify the surface of a sapphire heater to control the surface roughness, the layer thickness, and the surface chem...

[1] The Apollo lunar heat flow measurements gave values of 21 and 16 mW m 2 which, after extrapolation based on thorium abundances, yields a global estimate of 18 mWm . A refinement of the assumptions of the subsurface structure and the resulting focusing of heat flux later led to a revision of the global value to 12 mWm . We think that to date none of the models linking the Apollo heat flow me...

Critical heat flux (CHF) was measured for a water-cooled micro-channel heat sink containing 21 parallel 215· 821 lm channels. Tests were performed with deionized water over a mass velocity range of 86–368 kg/ms, inlet temperatures of 30 and 60 C, at an outlet pressure of 1.13 bar. As CHF was approached, flow instabilities induced vapor backflow into the heat sink’s upstream plenum, which signif...

A two-part experimental study is conducted on pool boiling heat transfer over enhanced cylindrical microchannel test surfaces with water at atmospheric pressure. In this Part II of the study, the effects of circumferential V-groove microchannels and axial rectangular microchannels are reported. These experiments were performed in the horizontal as well as vertical orientations. The heat transfe...

In this paper, a modified two-fluid model has been adopted to simulate the process of upward vertical subcooled flow boiling of refrigerant R-113 in a vertical annular channel at low pressure. The modified model considers temperature dependent properties and saturation temperature variation and was validated against a number of published low-pressure subcooled boiling experiments. The results s...

Laser forming is a modern process which is mainly used for forming metals. Different Lasers are used in this regard that includes Nd: YAG and CO2. In this study, forming bi-layer sheets of Aluminum/Ceramic by Laser was investigated. Furthermore, effect of Uniform and Gaussian heat flux distribution in different power, velocity, and beam diameters on bending angle was studied. FEM simulation ind...

Surface momentum, sensible heat, and latent heat fluxes are critical for atmospheric processes such as clouds and precipitation, and are parameterized in a variety of models ranging from cloud-resolving models to largescale weather and climatemodels. However, direct evaluation of the parameterization schemes for these surface fluxes is rare due to limited observations. This study takes advantag...

Critical heat flux (CHF) was measured and examined with high-speed video for subcooled flow boiling in micro-channel heat sinks using HFE 7100 as working fluid. High subcooling was achieved by pre-cooling the working fluid using a secondary low-temperature refrigeration system. The high subcooling greatly reduced both bubble departure diameter and void fraction, and precluded flow pattern trans...