Effect of wettability parameters of the heater porous structure on boiling heat transfer

The effect of wettability parameters of a porous heater material on boiling heat transfer was investigated using a hybrid numerical model based on the lattice Boltzmann method and the heat transfer equation. By simulating the boiling process on a porous heater with a regular hexagonal structure of rectangular metal heat-conducting elements at various thermal loads, boiling curves and coefficients of heat transfer enhancement/degradation were obtained for lyophilic, lyophobic, and neutral heater materials. The results showed that at moderately low thermal loads, the heat transfer coefficient on the lyophobic heater is higher than that for a surface with neutral wettability due to earlier initiation of the vapor phase, while at high thermal loads, heat transfer on the lyophilic heater is the greatest. It was also shown that the temperature of boiling onset is minimal for lyophobic heaters and maximal for lyophilic heaters, and the boiling crisis does not occur on a porous heater of any wettability even at the maximum heat loads considered.