The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform
Qiusheng Liu - One of the best experts on this subject based on the ideXlab platform.
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Transient Nucleate Boiling on a horizontal heated cylinder in liquid D-mannitol
Applied Thermal Engineering, 2018Co-Authors: Makoto Shibahara, Katsuya Fukuda, Qiusheng LiuAbstract:Abstract Various incipient Boiling heat fluxes and transient heat transfer coefficients of Nucleate Boiling on a horizontal heated cylinder in liquid D-mannitol were measured. A platinum cylinder was used as a heater in the experiment. The diameter and effective length of the platinum cylinder were 1.0 and 25.9 mm, respectively. The cylinder was heated by a DC power supply until the Nucleate Boiling regime in liquid D-mannitol was reached. The temperature of the liquid D-mannitol ranged from 455 to 502 K. The e-folding time of the heat generation rate ranged from 0.35 to 19 s. The incipient Boiling heat flux was dependent on the e-folding time of the heat generation rate, whereas the transient Nucleate Boiling heat transfer was not affected by the e-folding time of the heat generation rate. From the experimental data, the correlations of the incipient heat flux and the transient heat transfer coefficient were obtained.
Makoto Shibahara - One of the best experts on this subject based on the ideXlab platform.
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Transient Nucleate Boiling on a horizontal heated cylinder in liquid D-mannitol
Applied Thermal Engineering, 2018Co-Authors: Makoto Shibahara, Katsuya Fukuda, Qiusheng LiuAbstract:Abstract Various incipient Boiling heat fluxes and transient heat transfer coefficients of Nucleate Boiling on a horizontal heated cylinder in liquid D-mannitol were measured. A platinum cylinder was used as a heater in the experiment. The diameter and effective length of the platinum cylinder were 1.0 and 25.9 mm, respectively. The cylinder was heated by a DC power supply until the Nucleate Boiling regime in liquid D-mannitol was reached. The temperature of the liquid D-mannitol ranged from 455 to 502 K. The e-folding time of the heat generation rate ranged from 0.35 to 19 s. The incipient Boiling heat flux was dependent on the e-folding time of the heat generation rate, whereas the transient Nucleate Boiling heat transfer was not affected by the e-folding time of the heat generation rate. From the experimental data, the correlations of the incipient heat flux and the transient heat transfer coefficient were obtained.
Erik Bodegom - One of the best experts on this subject based on the ideXlab platform.
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Novel Approach to the Analysis of Fluctuations in Steady-State Nucleate Boiling
Advances in Cryogenic Engineering, 1994Co-Authors: Eric W. Roth, J. S. Semura, L. C. Brodie, Erik BodegomAbstract:In observations of steady-state Nucleate Boiling, fluctuations in the temperature and heat flux might initially appear completely random. However, we show that in a more detailed examination, the observed fluctuations about the steady-state, in fact, exhibit an average counterclockwise circulation when the heat flux is plotted versus the superheat temperature. We present experimental evidence for this circulation in the Nucleate Boiling of liquid nitrogen from a platinum wire and an explanation of this circulation is presented. An area associated with the average circulation is also proposed as a numerical measure of stability for steady-state Nucleate Boiling. Such a measure could be of practical importance in anticipating a transition to film Boiling.
Sherman C.p. Cheung - One of the best experts on this subject based on the ideXlab platform.
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Nucleate Boiling of dilute nanofluids – Mechanism exploring and modeling
International Journal of Thermal Sciences, 2014Co-Authors: Sherman C.p. CheungAbstract:Despite the overall merits of using nanofluids as heat transfer fluids are still under controversy in many fields, their application in nuclear reactor systems, especially the IVR system has been proved to be promising. However, the lack of fundamental understanding of the physical mechanisms has hindered the applications. For the purpose of developing a mechanistic model of Nucleate Boiling of nanofluids for nuclear applications, the common findings yielded from most experimental investigations available in the literature are analyzed in this study. It was demonstrated that the heater surface modification induced by nanoparticle deposition during the Boiling process is the major cause of the dramatic Boiling heat transfer performance of nanofluids. It was further suggested that the classic heat partitioning model is applicable to predicting Nucleate Boiling of nanofluids on condition that the surface modification and the Nucleate Boiling parameters (e.g. the active site density, the bubble departure diameter and frequency) are properly formulated.
Catherine Colin - One of the best experts on this subject based on the ideXlab platform.
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Transient flow Boiling in a semi-annular duct: From the Onset of Nucleate Boiling to the Fully Developed Nucleate Boiling
International Journal of Heat and Mass Transfer, 2019Co-Authors: V. Scheiff, Nicolas Baudin, Pierre Ruyer, Julien Sebilleau, Catherine ColinAbstract:Abstract This paper presents an investigation of the transient Onset of Nucleate Boiling (ONB) on a vertical heated surface cooled by an upward flow. The duct geometry used (semi-annulus with a heated inner wall) make this study very similar to a fuel rod in a Pressurised Water Reactor (PWR). This test section is then heated with different power steps to show the ONB and observe its propagation along the wall. The fluid used is the refrigerant HFE7000 flowing with flow rates corresponding to Reynolds numbers from 0 to 60,000 and subcoolings Jakob numbers from 8 to 33. Synchronised infra-red (IR) thermal measurements and high-speed camera visualizations provided new data which helped to develop models to characterise the Onset of Nucleate Boiling and the transition to the Fully Developed Nucleate Boiling regime (FDNB). This very finely characterized local behaviour provides an original insight for the onset of Nucleate Boiling in such sub-cooled convective configuration. It is shown that Boiling is initiated by nucleation at a few specific sites and then propagates in the wake of a large vapor pocket flowing along the wall. Analysis of wall to fluid heat transfer evidences a short heat transfer degradation phase below the first vapor pocket, followed by a very effective cooling in its wake. The wall to fluid heat transfer during this transition toward fully developed Nucleate Boiling appears uncorrelated to the power dissipated within the heating element or to flow conditions.
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Transient flow Boiling in a semi-annular duct: From the Onset of Nucleate Boiling to the Fully Developed Nucleate Boiling
International Journal of Heat and Mass Transfer, 2019Co-Authors: V. Scheiff, Nicolas Baudin, Pierre Ruyer, Julien Sebilleau, Catherine ColinAbstract:This paper presents an investigation of the transient Onset of Nucleate Boiling (ONB) on a vertical heated surface cooled by an upward flow. The duct geometry used (semi-annulus with a heated inner wall) make this study very similar to a fuel rod in a Pressurised Water Reactor (PWR). This test section is then heated with different power steps to show the ONB and observe its propagation along the wall. The fluid used is the refrigerant HFE7000 flowing with flow rates corresponding to Reynolds numbers from 0 to 60,000 and subcoolings Jakob numbers from 8 to 33. Synchronised infra-red (IR) thermal measurements and high-speed camera visualizations provided new data which helped to develop models to characterise the Onset of Nucleate Boiling and the transition to the Fully Developed Nucleate Boiling regime (FDNB). This very finely characterized local behaviour provides an original insight for the onset of Nucleate Boiling in such sub-cooled convective configuration. It is shown that Boiling is initiated by nucleation at a few specific sites and then propagates in the wake of a large vapor pocket flowing along the wall. Analysis of wall to fluid heat transfer evidences a short heat transfer degradation phase below the first vapor pocket, followed by a very effective cooling in its wake. The wall to fluid heat transfer during this transition toward fully developed Nucleate Boiling appears uncorrelated to the power dissipated within the heating element or to flow conditions.
