The artificial surfaces are applied to study the pool boiling features, including the bubble behaviors, the surface temperature fluctuation, the heat transfer characteristics and nucleate site interaction. Three sets ...The artificial surfaces are applied to study the pool boiling features, including the bubble behaviors, the surface temperature fluctuation, the heat transfer characteristics and nucleate site interaction. Three sets of experiments are carried out to investigate the influences of cavity shape, cavity size, cavity spacing on the boiling phenomena. Experimental results reveal that bubbling from the cylindrical as well as reentrant cavity is generally stable. The influence of cavity diameter on the bubble behaviors and the temperature fluctuation seems very weak while the effect of cavity depth cannot be neglected. As for the two cavity conditions, the bubble behaviors show the different features depending on the dimensionless cavity spacing. Three significant factors (thermal interaction, hydraulic interaction, bubble coalescence) control the nucleation site interaction, and the competition and dominance of the factors yield four interaction regimes.展开更多
Recently we have constructed two facilities for generating photon beams in the MeV and sub-MeV energy regions by means of the Compton backscattering with a laser and an electron beam at SPring-8 and at Kansai Photon S...Recently we have constructed two facilities for generating photon beams in the MeV and sub-MeV energy regions by means of the Compton backscattering with a laser and an electron beam at SPring-8 and at Kansai Photon Science Institute of Japan Atomic Energy Agency(KPSI-JAEA). The MeV-photon source at SPring-8 consists of a continuous-wave optically-pumped far infrared laser with a wavelength of 118.8 μm and an 8 GeV stored electron beam. Present MeV-photon flux is estimated to be 1.3×103 photons/s. On the other hand,the sub-MeV-photon source at KPSI-JAEA consists of a pulse Nd∶YAG laser with a wavelength of 1 064 nm and a 150 MeV electron beam accelerated by microtron. In the first trial of the photon production in this source,backscattered photon flux is estimated to be 20 photons/pulse. Both the Compton backscattered photon sources have possibilities to be used for new tools in various fields such as nuclear physics,materials science,and astronomy.展开更多
基金The authors would like to express their gratitude to Prof. D.J. Lee of National Taiwan University who has provided many suggestions to the present research on nucleation site interaction.
文摘The artificial surfaces are applied to study the pool boiling features, including the bubble behaviors, the surface temperature fluctuation, the heat transfer characteristics and nucleate site interaction. Three sets of experiments are carried out to investigate the influences of cavity shape, cavity size, cavity spacing on the boiling phenomena. Experimental results reveal that bubbling from the cylindrical as well as reentrant cavity is generally stable. The influence of cavity diameter on the bubble behaviors and the temperature fluctuation seems very weak while the effect of cavity depth cannot be neglected. As for the two cavity conditions, the bubble behaviors show the different features depending on the dimensionless cavity spacing. Three significant factors (thermal interaction, hydraulic interaction, bubble coalescence) control the nucleation site interaction, and the competition and dominance of the factors yield four interaction regimes.
基金Japan Societyfor Promotion of Science under Grant-and Aid for Scientific Research(14205018)Ministry of Educa-tion,Science,Sports and Culture of Japan under Grant-and-Aid for Specially Promoted Research (15002013)
文摘Recently we have constructed two facilities for generating photon beams in the MeV and sub-MeV energy regions by means of the Compton backscattering with a laser and an electron beam at SPring-8 and at Kansai Photon Science Institute of Japan Atomic Energy Agency(KPSI-JAEA). The MeV-photon source at SPring-8 consists of a continuous-wave optically-pumped far infrared laser with a wavelength of 118.8 μm and an 8 GeV stored electron beam. Present MeV-photon flux is estimated to be 1.3×103 photons/s. On the other hand,the sub-MeV-photon source at KPSI-JAEA consists of a pulse Nd∶YAG laser with a wavelength of 1 064 nm and a 150 MeV electron beam accelerated by microtron. In the first trial of the photon production in this source,backscattered photon flux is estimated to be 20 photons/pulse. Both the Compton backscattered photon sources have possibilities to be used for new tools in various fields such as nuclear physics,materials science,and astronomy.
