It is known, that the phenomena of phase change and boiling crisis are not yet fully deciphered, which leads to generation technical problems, such as frequent breakdowns accidental shutdowns in thermal installations. The main objective this study numerical analysis an ascending flow during a vertical channel by Relap5/Mod3.2 code. This code can helps heat transfer convection, boiling, condensa...

An experimental investigation of the boiling-up dynamics a jet superheated water being discharged through short nozzle small diameter (d=0.2 mm) has been conducted. A change in shape traced at various degrees superheat. complete flow opening established temperature range T=493-583 K. The instability breakup revealed. On basis data, dependence variations angle on saturation pressure plotted dime...

Experiments are conducted with a perfluorinated dielectric fluid, Fluorinert FC-77, to investigate the effects of channel size and mass flux (225–1420 kg/ms) on microchannel flow boiling regimes by means of high-speed photography. Seven different silicon test pieces with parallel microchannels of widths ranging from 100 to 5850 lm, all with a depth of 400 lm, are considered. Flow visualizations...

This study aims to better characterize the heat transfer and flow structure in fully developed nucleate boiling regime a semi-annular duct. Experiments with refrigerant HFE7000 were performed range of Reynolds numbers from 13 000 40 500, subcoolings close 15 ?C, for constant heating power, wall temperature rates (linear increase temperature). With flux is well predicted by Chen-type correlation...

The paper presents CFD code validation and benchmarking against the NUPEC BFBT (BWR FullSize Fine-Mesh Bundle Tests) data, performed within the OECD/NRC BFBT void distribution benchmark and as part of the NURESIM (European Platform for Nuclear Reactor Simulations) Integrated Project. Sub-cooled flow boiling occurs in many industrial applications and is characterized by large heat transfer coeff...

The effect of flow instabilities on flow boiling heat transfer in microchannels is investigated using water as the working fluid. The experimental test section has six parallel rectangular microchannels with each having a cross sectional area of 1054 × 197 microns. Flow restrictors are introduced at the inlet of each microchannel to stabilize the flow boiling process and avoid the backflow phen...

Experiments were performed to measure the incipient boiling heat flux in a heat sink containing 21 rectangular (231 lm wide and 713 lm deep) micro-channels. Tests were performed using deionized water with inlet liquid velocities of 0.13–1.44 m/s, inlet temperatures of 30, 60 and 90 C, and an outlet pressure of 1.2 bar. Using a microscope, boiling incipience was identified when the first bubbles...