Numerical calculation of thermosyphon boiling heat transfer in lunate channel

Thermosyphon boiling heat transfer in lunate channel can enhance heat transfer evidently. The experimental study proves that boiling heat transfer coefficient of LiBr water solution approaches to 5-6 kW/(m²·K). On the base of thin film evaporation mechanism of the channel, a comprehensive heat transfer model for thermosyphon boiling in narrow channel is developed. It is shown that the temperature distribution gradually becomes linear with time. The thickness of liquid film decreases with increasing heat flux, and boiling heat transfer coefficient increases with increasing heat flux. The evaporating heat transfer performance of the thin liquid film beneath bubbles is analyzed under different boundary conditions and initial conditions, and it is explained that the heat transfer coefficient is greatly enhanced due to the decreased thickness of thin film beneath flattened bubbles. This model is demonstrated to be reasonable by the fact that the results predicted by this model are coincided well with experimental ones.