Simple Flow-Pattern Based Heat Transfer Correlations for Flow Boiling in Micro/Minichannels

Zan Wu, Bengt Sundén, Shi-chune Yao, Vishwas V. Wadekar, Wei Li

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceedingpeer-review


An improved conventional-to-micro/minichannel threshold was proposed as Bo = 4 and BoRe(1)(0.5) = 200, where Bo is the Bond number and Re-1 is the liquid Reynolds number. The region Bo < 4 and BoRe(1)(0.5) < 200 is termed as micro/minichannel because bubbles tend to be confined and elongated in the channel and the conventional two-phase flow theory loses its applicability. Flow-pattern based heat transfer correlations for elongated bubbly flow and annular flow in flow boiling micro/minichannels were developed separately based on a collected micro/minichannel heat-transfer database. As significant disagreement in experimental trends and heat transfer mechanisms was reported for flow boiling in micro/minichannels in the literature, it is not possible to explain the discrepancy and predict all data points by a single correlation without considering the different flow patterns. The newly developed flow-pattern based predictive tool can not only present a decent overall accuracy, but also estimate the parametric trends correctly. Over 95% of the data points can be predicted by the proposed correlations within a +/- 50% error band for both elongated bubbly flow and annular flow. Therefore, the simple flow-pattern based correlations can be applied for heat exchanger design, improve understanding of the underlying heat transfer mechanisms, and guide development of further enhancement techniques for flow boiling in micro/minichannels.
Original languageEnglish
Title of host publicationProceedings of the Asme 12th International Conference on Nanochannels, Microchannels, and Minichannels, 2014
PublisherAmer. Soc. Mechanical Engineers
Publication statusPublished - 2014
Event12th International Conference on Nanochannels, Microchannels and Minichannels (ICNMM) - Chicago, IL
Duration: 2014 Aug 32014 Aug 7


Conference12th International Conference on Nanochannels, Microchannels and Minichannels (ICNMM)

Subject classification (UKÄ)

  • Energy Engineering


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