During flow boiling in microchannels, the physics of a bubble is closely related to the heat transfer performance of different hydrophobic patterns. However, the heat transfer properties of various patterns are yet to be investigated. In this study, we conducted a numerical investigation into bubble coalescence characteristics and heat transfer performance of three patterns, namely crosswise, parallel, and dotted patterns, for flow boiling in a microchannel, and evaluated the influence of the hydrophobic area fraction for each pattern. In the transport equation, we employed a mass transfer model based on a two-phase mixture flow for the vaporization and condensation processes. In addition, we used the volume-of-fluid method to track the dispersed phase's interface using the local volume fraction. Although the parallel pattern at low mass flux facilitating bubble movement exhibited a good heat transfer performance, the dotted pattern displayed a better performance at high mass fluxes due to its higher nucleation site density. Additionally, very wide or narrow hydrophobic areas are unsuitable for heat transfer. Narrow areas limit bubble nucleation. A hydrophobic area fraction of 0.165 for the crossed pattern and of 0.32 for the parallel and dotted pattern produced the best heat transfer performances.
|Journal||International Journal of Heat and Mass Transfer|
|Publication status||Published - 2020 Jun|
Bibliographical noteFunding Information:
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education ( NRF-2019R1A6A3A01096772 ). This work was also supported by the National Research Foundation of Korea (NRF) Grant funded by the Korean Government (MSIP) (No. 2015R1A5A1037668 ).
© 2020 Elsevier Ltd
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Mechanical Engineering
- Fluid Flow and Transfer Processes