Silver dendrite decorated microporous copper structures for the enhancement of nucleate boiling heat transfer

Abstract

Abstract This study explores the augmentation of nucleate boiling heat transfer by surface modification of copper through a combination of electrodeposition and galvanic exchange reaction (GER). A novel microporous copper network adorned with silver dendrites was synthesized to boost the nucleate boilig heat transfer. The boiling characteristics such as heat transfer coefficient (HTC), onset of boiling (ONB), and bubble dynamics were experimentally studied for copper deposite with silver coatings produced at varying concentrations of silver ions (100, 200, and 400 mg/L) and immersion times (60, 80, and 300 s). Among the samples tested, the copper deposite coated with silver dendrites at 400 mg/L for 300 seconds (sample S5) exhibited the most substantial enhancement. Compared to the performance of the bare copper surface, sample S5 demonstrated a remarkable 163.61% increase in the heat transfer coefficient and a notable 61.11% reduction in wall superheat. This result can be attributed to the well-developed silver dendrites and the availability of micropores, facilitating hinderance-free bubble emanation.The factors governing the enhancement includes the microporous structure of the deposits, the high purity of the coating, and the surplus nucleation sites provided by the dendritic nature of silver.