A thermal-hydrodynamic coupling method for simulating the interplay between bubble departure and wall temperature variation in nucleate boiling

A thermal-hydrodynamic coupling model is used to investigate the interplay between the wall temperature distribution and the bubble departure during the nucleate boiling process. The boiling process is modeled as the combination of three subprocesses: the transient heat conduction process in the solid heater, the evaporation of the microlayer underneath the bubble, and the bubble dynamics in the two-phase bulk fluid region. The moving bubble interface is captured by the volume of fluid method in the OpenFOAM framework. The proposed model is validated against the experimental results of the boiling process of the water on an Indium Tin Oxide heater. The predicted results agree well with related measurements in the literature. Following the validation, the effects of the boiling heat flux on the bubble departure period are examined. The results show that the bubble departure period decreases with the increase of the applied heat flux. High heat flux will cause irregularity in the departure periods for successive bubbles due to the influence of the wake flow evoked by the rising bubble. Furthermore, the influence of the bubble contact angle on the boiling heat-transfer performance is investigated. It is confirmed that the bubble departure diameter increases with the increase of the contact angle, meanwhile, the average wall temperature decreases with the increase of the contact angle.