Effect of silicon nanorod length on horizontal nanostructured plates in pool boiling heat transfer with water

An experimental study was conducted to investigate the effect of nanorod length on pool boiling heat transfer of water from nanostructured surfaces. Three nanostructured plates featuring Si nanorods of diameter 850 nm and of three different lengths (900, 1800 and 3200 nm), which were etched through single crystal p-type silicon wafers using metal-assisted chemical etching (MaCE), were utilized to enhance pool boiling heat transfer. Nanostructured plates were placed on the bottom of a heated aluminum pool inside a Plexiglas container filled with water, and the surface temperatures of nanostructured plates were measured at increasing heat flux values to quantify boiling heat transfer enhancements, which were obtained with changing the surface morphology using nanostructured plates of different Si nanorod lengths. The experiments were repeated using a plain surface Si plate. A visualization study on bubble formation and release from individual plates was conducted using a high speed camera to bolster the experimental results. Compared to the plain Si surface, boiling heat transfer enhancements up to 254% and 120% were attained using the shortest and longest nanorod configurations, respectively.