Role of inter-nanowire distance in metal nanowires on pool boiling heat transfer characteristics.

Graphical abstract Pool boiling performance of nanowire coated surfaces. The CHF and heat transfer coefficient (h) of both CuNW and AgNW coated surfaces increases with increase in the inter-nanowire distances. Abstract Energy management in data centres is crucial where a maximum portion of energy is spent on thermal management and electronics cooling systems. It becomes very crucial when it comes to immersion cooling technique s (pool boiling mechanism) using dielectric fluids. Role of metal nanowires (Cu and Ag) with different inter-nanowire distance values were analysed for their pool boiling performance. Templates with different inter-pore distances (260 ± 20 nm, 320 ± 20 nm and 360 ± 20 nm) and diameter of 200 nm were used to deposit copper nanowires (CuNW) and silver nanowires (AgNW) over the copper substrate using electrodeposition technique. Electrodeposition conditions like voltage and time were optimised to obtain nanowires of near constant height and different surface density coverage. To investigate the role of these metal nanowires on pool boiling characteristics, a dedicated pool boiling experimental facility was fabricated and experiments were carried out using FC-72 as working fluid. As a result of experimental investigation, boiling incipience superheat was observed to reduce which is very important for electronics systems. Also, both the critical heat flux (CHF) and heat transfer coefficient (h) were found to be increased as compared to the bare copper surface. Increasing the distance between nanowires, decreases the number of nanowires per unit area and thus the surface density coverage. This increases the cavity density and cavity size of micron-scale cavities in favour of pool boiling enhancement. This also decreases the resistance to fluid flow at high heat flux values which delays the surface dryout and critical heat flux. [ABSTRACT FROM AUTHOR]