How is the heat transfer in two-phase flow related to single-phase flow? A new theory is proposed in our recent paper to answer this question.

The paper focuses on two-phase annular flow during condensation. We developed a simple, physics-based model that considers the thermal resistances for the boundary layers near the wall and the liquid-vapor interface. The model yields an analytical expression for the two-phase multiplier, suggesting that it scales linearly with the inverse of the liquid fraction. This is confirmed by experimental data. The scaling factor is linked to the dimensionless interface velocity (i.e., ratio of interface velocity to mean liquid velocity), which can be approximated as a universal constant. The model achieves prediction accuracy comparable to the existing empirical correlations, while offering the additional benefit of providing a physically grounded framework that can be further adapted and refined.

Congrats to Chase Yankowski, our first PhD student, on publishing his first (& Lin Lab’s first) journal paper. Look forward to more insights and discoveries coming out of this project.