Experimental study of electrospray deposition method parameters on TiO_2 coating structure in pool boiling performance enhancement
Abbas Haji, Hesam Moghadasi, Hamid Saffari
Abstract
In this research work, pool-boiling heat transfer is conducted with the consideration of TiO2 hydrophilic nanoparticles as coating material using Electrospray Deposition (ESD) method. The study focused on the impact of spray parameters such as injection flow rate, solution concentration, and spray time on the formation of the coating structure, porosity, cavity characteristics, and thickness. Moreover, X-ray diffraction (XRD), Energy Dispersive X-ray spectroscopy (EDX), Profilometric Analysis, and Scanning Electronic Microscopy (SEM) images were utilized to analyze the surfaces. As a result, pool boiling was ameliorated by reaching the effective cavity size, rewetting the surface, and improving the bubble departure mechanism. Furthermore, the coating’s stability and adhesion were examined in the boiling results, due to the existence of a small decrease in the curves. The optimal case increased the Maximum Heat Flux (MHF) and maximum Heat Transfer Coefficient (HTC) up to 90% and 118.3%, respectively. In addition, reduced the superheat temperature to 31.7% relative to the plain copper surface.