This research presents experimental approaches to accumulate the data for mechanistic model in subcooled flow boiling. A number of photographic studies have been provided to investigate phenomena of bubble nucleation and condensation process for accurate prediction of void fraction such as bubble detachment diameter, bubble detachment frequency and nucleation site density in a subcooled flow boiling. In this work, a transparent heated surface was used to obtain the data from back side of heated surface to avoid overlapping bubbles by using high speed video camera. It enabled to observe bubble nucleation process and active nucleation sites. The experiment was performed in a vertical rectangular channel at atmospheric pressure and the water was used as test fluid. In generally, the computational analysis for a subcooled flow boing deal with mean bubble size as the size of bubbles produced on heated surface. Although, it was found that mean bubble size can represent bubbles produced at same site because they are almost uniform size. Even though the size of bubbles at same site are almost uniform, the difference of the size of bubbles between other sites are considerable value. Therefore, mean bubble size on the surface should not represent bubbles for all site otherwise the serious error may be caused. It seems that bubble detachment diameter should not be given by correlations of mean bubble detachment diameter for accurate prediction of vaporization rate. Some researchers proposed that bubble size distribution should be considered by Gaussian distribution [1–3]. However, it found that bubble size distribution data accumulated in this work cannot be fitted by Gaussian distribution and there are probability that larger bubbles are neglected due to the configuration features of Gaussian distribution. So, Gamma distribution was used to predict the bubble size distribution and it was evaluated in terms of heat flux, wall superheat, mass flux and liquid subcooling. And then, by the experimental approaches, the important dimensionless parameters are identified such as Nusselt number, Jakob number, Reynolds number and dimensionless subcooling. Furthermore, vaporization rate was calculated by correlations of bubble detachment diameter, bubble detachment diameter and nucleation site density and compared with the data. Finally, the effect of using mean bubble size or bubble size distribution on vaporization rate was investigated.
Skip Nav Destination
2016 24th International Conference on Nuclear Engineering
June 26–30, 2016
Charlotte, North Carolina, USA
Conference Sponsors:
- Nuclear Engineering Division
ISBN:
978-0-7918-5005-3
PROCEEDINGS PAPER
Accurate Estimation of Vaporization Rate in Subcooled Flow Boiling Based on the Results of Visualization Experiment
Kazuhiro Kaiho,
Kazuhiro Kaiho
The University of Electro-Communications, Tokyo, Japan
Search for other works by this author on:
Koji Enoki,
Koji Enoki
The University of Electro-Communications, Tokyo, Japan
Search for other works by this author on:
Tomio Okawa
Tomio Okawa
The University of Electro-Communications, Tokyo, Japan
Search for other works by this author on:
Kazuhiro Kaiho
The University of Electro-Communications, Tokyo, Japan
Koji Enoki
The University of Electro-Communications, Tokyo, Japan
Tomio Okawa
The University of Electro-Communications, Tokyo, Japan
Paper No:
ICONE24-60318, V005T15A019; 10 pages
Published Online:
October 25, 2016
Citation
Kaiho, K, Enoki, K, & Okawa, T. "Accurate Estimation of Vaporization Rate in Subcooled Flow Boiling Based on the Results of Visualization Experiment." Proceedings of the 2016 24th International Conference on Nuclear Engineering. Volume 5: Student Paper Competition. Charlotte, North Carolina, USA. June 26–30, 2016. V005T15A019. ASME. https://doi.org/10.1115/ICONE24-60318
Download citation file:
13
Views
Related Proceedings Papers
Related Articles
Investigation of the Influence of Elevated Pressure on Subcooled Boiling Flow—Model Evaluation Toward Generic Approach
J. Heat Transfer (July,2017)
Numerical Simulation of Evaporating Two-Phase Flow in a High-Aspect-Ratio Microchannel with Bends
J. Heat Transfer (August,2017)
Steady-State Subcooled Nucleate Boiling on a Downward-Facing Hemispherical Surface
J. Heat Transfer (May,1998)
Related Chapters
Global Mode Visualization in Cavitating Flows
Proceedings of the 10th International Symposium on Cavitation (CAV2018)
Energy Balance for a Swimming Pool
Electromagnetic Waves and Heat Transfer: Sensitivites to Governing Variables in Everyday Life
Thermal Design Guide of Liquid Cooled Systems
Thermal Design of Liquid Cooled Microelectronic Equipment