A new model, based on the experimental observation reported in the literature that CHF is triggered by the Irreversible Hot Spots (IHS), has been developed to predict the Critical Heat Flux (CHF) in pool boiling. The developed Irreversible Hot Spot (IHS) model can predict the CHF when boiling methanol on small flat surfaces and long horizontal cylinders of different sizes to within 5% uncertainty. It can also predict the effect of changing wettability (i.e. contact angle) on CHF to within 10% uncertainty for both hydrophilic and hydrophobic surfaces. In addition, a linear empirical correlation has been developed to model the bubble growth rate as a function of the system pressure. The IHS model with this linear bubble growth coefficient correlation can predict the CHF when boiling water on both flat surfaces and long horizontal cylinders to within 5% uncertainty up to 10 bar system pressure, and the CHF when boiling methanol on a flat surface to within 10% uncertainty up to 5 bar. The predicted detailed bubble grow and
merge process from various sub-models are also in good agreement with the experimental results reported in the literature.
History
School
Mechanical, Electrical and Manufacturing Engineering
Published in
International Journal of Multiphase Flow
Volume
104
Pages
174 - 187
Citation
ZHAO, H. and WILLIAMS, A.M., 2018. Predicting the critical heat flux in pool boiling based on hydrodynamic instability induced irreversible hot spots. International Journal of Multiphase Flow, 104, pp.174-187.
This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/
Acceptance date
2018-02-27
Publication date
2018-03-07
Notes
This paper was published in the journal International Journal of Multiphase Flow and the definitive published version is available at https://doi.org/10.1016/j.ijmultiphaseflow.2018.02.021.