A proper observation and characterization of wall nucleation phenomena in a forced convective boiling system

Abstract Experimental information regarding fundamental bubble parameters such as bubble departure diameter and bubble departure frequency is crucial for the development and validation of mechanistic models to treat the wall nucleation phenomena in a forced convective boiling system. However, a thorough review of the literature reveals that there are several unidentified issues in the previous experimental works, issues which have never been explicitly addressed despite their possibly critical impact on the experimental results. Also, the experimental efforts are still being made without properly addressing the impact of those issues. Thus, in an effort to reveal such issues and to verify the errors created by not addressing them, we performed a series of systematic experimental investigations to evaluate the impacts of these issues and to subsequently make recommendations. The explored issues include (i) the effect of different measurement views on the observation of the nucleating bubbles; (ii) the effect of applying different visualization recording speeds; and (iii) the effect of the number of experimental observations (i.e., sample size) on the statistics of measured bubble parameters. Then, based on the findings, more appropriate ways of observing and characterizing the fundamental bubble parameters were discussed. Additionally, an image analysis method was developed to efficiently and accurately extract the quantitative information of fundamental bubble parameters from the experimental images of boiling bubbles. The performance of this method was tested in subcooled boiling flow circumstances, and it seems promising as a means of analyzing the vast number of images required to satisfy the high statistical demands to characterize wall nucleation features. The experimental findings and discussions in the present study will provide valuable guidance towards the proper investigation of the wall nucleation phenomena in a subcooled flow boiling system or, more generally, in a forced convective boiling system.

[1]  Renwei Mei,et al.  Vapor bubble departure in forced convection boiling , 1993 .

[2]  T. Okawa,et al.  Simultaneous measurement of void fraction and fundamental bubble parameters in subcooled flow boiling , 2007 .

[3]  Vijay K. Dhir,et al.  Wall Heat Flux Partitioning During Subcooled Flow Boiling: Part 1—Model Development , 2005 .

[4]  J. Klausner,et al.  Nucleation Site Density in Forced Convection Boiling , 1993 .

[5]  Michitsugu Mori,et al.  Bubble rise characteristics after the departure from a nucleation site in vertical upflow boiling of subcooled water , 2005 .

[6]  V. I. Tolubinsky,et al.  On the mechanism of boiling heat transfer (vapour bubbles growth rate in the process of boiling of liquids, solutions, and binary mixtures) , 1966 .

[7]  Renwei Mei,et al.  An experimental investigation of bubble growth and detachment in vertical upflow and downflow boiling , 1998 .

[8]  M. Ishii,et al.  Interfacial area transport of subcooled boiling flow in a vertical annulus , 2014 .

[9]  Nilanjana G. Basu.  Modeling and experiments for wall heat flux partitioning during subcooled flow boiling of water at low pressures , 2003 .

[10]  S. J. Kline,et al.  Describing Uncertainties in Single-Sample Experiments , 1953 .

[11]  V. Ilchenko,et al.  Study of the bubble characteristics and the local void fraction in subcooled flow boiling using digital imaging and analysing techniques , 2002 .

[12]  Chul-Hwa Song,et al.  Characteristics of Bubble Departure Frequency in a Low-Pressure Subcooled Boiling Flow , 2010 .

[13]  R. J. Moffat,et al.  Contributions to the Theory of Single-Sample Uncertainty Analysis , 1982 .

[14]  R. Mei,et al.  A unified model for the prediction of bubble detachment diameters in boiling systems—II. Flow boiling , 1993 .

[15]  Stanley R. Sternberg,et al.  Biomedical Image Processing , 1983, Computer.

[16]  V. Ilchenko,et al.  Automated high-speed video analysis of the bubble dynamics in subcooled flow boiling , 2004 .

[17]  J. Westwater,et al.  Microscopic study of bubble growth during nucleate boiling , 1961 .

[18]  Martha Salcudean,et al.  Bubble behavior in subcooled flow boiling of water at low pressures and low flow rates , 2002 .

[19]  Nilanjana G. Basu,et al.  Onset of Nucleate Boiling and Active Nucleation Site Density During Subcooled Flow Boiling , 2002 .

[20]  Hee Cheon No,et al.  Bubble Lift-off Diameter and Nucleation Frequency in Vertical Subcooled Boiling Flow , 2011 .

[21]  Renwei Mei,et al.  Predicting stochastic features of vapor bubble detachment in flow boiling , 1997 .

[22]  Michitsugu Mori,et al.  Bubble Lift-off Size in Forced Convective Subcooled Boiling Flow , 2005 .

[23]  G. H. Yeoh,et al.  Assessment of effect of Bubble Departure Frequency in Forced Convective Subcooled Boiling Flow , 2008 .

[24]  M. Ishii,et al.  Thermo-Fluid Dynamics of Two-Phase Flow , 2007 .

[25]  Basar Ozar.  Interfacial area transport of steam-water two-phase flow in a vertical annulus at elevated pressures , 2009 .