The Manufacture Of Nanoporous Copper Surface Structure And Its Pool Boiling Enhancement Performance

Nanoporous structures can effectively improve the heat transfer area, improved surface wettability, maintaining excellent thermal conductivity, enhance the potential vaporization core density, which has a promising application in enhancement of boiling heat transfer. Boiling heat transfer can provide tremendous heat transfer coefficient under a low superheat condition due to the latent heat of working fluid during phase transition process, which is recognized as an effective way for heat transfer. Pool boiling enhancement can improve energy efficiency and cooling high power devices, which has been widely used in traditional industry such as thermal power, new energy, nuclear power, petrochemical et al. and high-tech field like microelectronic.In this study, a novel in-situ nanostructure forming route: electroplating/thermal diffusion/dealloying is adopted to obtain nanoporous copper surfaces. Parameters such as the temperature and time of heat treatment, dealloying solution, dealloying time have a significant impact on surface characteristics(surface morphology, chemical composition and surface wettability) of nanoporous surface.A pool boiling test platform has been designed and built to conduct saturation heat transfer performance experiment. The obtained nanoporous copper surface significantly enhances heat transfer coefficient, reduces wall superheat and effectively improves the critical heat flux compared to flat surface, due to its uniform three-dimensional continuous porosity, single copper component and good wettability. Through contacting the differences of bubble dynamics characteristics between nanoporous surface and flat surface under different heat flux, and taking their heat transfer performance and surface properties into condition, the enhancement pool boiling heat transfer mechanism of nanoporous surface has been analyzed. In saturated pool boiling environment, nanoporous surface which in nucleate boiling stage for a long period, can hold good chemical stability and self-similar evolution morphology.A micro-nano composite surface has been prepared successfully due to convenience operational property of the adopted in-situ nanostructure forming route. Micro-nano composite surface combines the advantages of micro-channel structure and nanoporous structure, which has further increases pool boiling heat transfer coefficient and critical heat flux.