ABSTRACT
In this research work, pool-boiling heat transfer is conducted with the consideration of 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.
Nomenclature
Symbols
area (m2)
T temprature (K)
a constant value of Rohsenow (dimensionless)
latent heat of vaporization (J/kg)
Greek Symbols
Abbreviations
ESDelectrospray deposition
CHFcritical heat flux
MHFmaximum heat flux
HTCheat transfer coefficient
XRDx-ray diffraction
EDXenergy dispersive x-ray spectroscopy
SEMscanning electron microscopy
DAQdata acquisition system
PTFE polytetrafluoroethylene
RTDresistance temperature detector
Wt.weight fraction
Disclosure statement
No potential conflict of interest was reported by the author(s).