The spray cooling and heat removal efficiency is one of the important aspect of nuclear thermalhydraulics and safety, especially for passive containment cooling after severe accidents. In order to design and optimize these systems effectively, computer modelling of the underlying mechanism of the liquid drop interaction with the hot solid surface would be necessary. Therefore, completeness, accuracy and reliability of the models that are being used in such sensitive areas are vital to the society and environment. Furthermore, the current powerful computer resources need to be fully exploited, so that the precision and the accuracy of the obtained computational results would be further enhanced. Nowadays, Volume-Of-Fluid (VOF) method is widely used in simulating the droplet dynamics, however these models provide estimations that are different in certain extents compare to the experimental results. In present work, we have used the level-set method to study the droplet dynamics and heat removal when the water droplet impact on the surface with different morphologies. The developed model which is based on the finite element method (FEM) has been benchmarked with previously performed experiments regarding the droplet bouncing on a flat hydrophobic surface; these estimations were in a good agreement with the previously published results. Moreover, hot solid surfaces with presence of micro-pillar has been considered to perform sensitivity study for different sizes of the micro-pillars and water droplets. In addition, it has been found that the heat transfer and droplet dynamic behavior would significantly vary in scenarios when the micro-pillars are presents in compare to a flat solid surface; it is observed that a better droplet spreading can be obtained with optimal size of micro-pillars that are present underneath of the droplet axial trajectory. The present study and the model would add valuable information to the field of heat transfer in aspect of spray cooling by investigating the feasibility of using the level-set method for a better estimation of fluid and heat transfer related results.
Experimental Investigation of the Influences of Fluid Properties on
Heat Transfer for Spray Cooling
