A mechanistic full bubble lifecycle model in subcooled flow boiling—from nucleation on the wall to collapse in the mainstream

Abstract

Accurately simulating the evolution of bubbles in subcooled flow boiling is of great significance for improving the simulation accuracy of flow boiling heat transfer. Although refined numerical simulations have made it possible to accurately model individual boiling bubble, there is still a lack of bubble models that are both mechanistically explicable and computational cost-effective. In this paper, we have proposed a mechanistic model that can simulate the full bubble lifecycle from nucleation on the wall to collapse in the subcooled mainstream. Even though the process is quite complex, the number of fitting parameters used has been reduced to just one, namely the static contact angle. The evaporation of the microlayer and the near-wall superheated layer adopts a mechanistic model that is more in line with physical principles, rather than the commonly used empirical correlations. Experimental data from four different researchers were used for validation, proving that this model has a satisfactory ability to predict the evolution of bubbles during flow boiling. Finaly, the separate effects of contact angle, mass flux, wall superheat degree and mainstream subcooling degree on the full bubble lifecycle evolution were studied.