Pool Boiling Enhancement Mechanisms in Multi Scaled Carbon-Based Morphologies

摘要

Pool boiling heat transfer is an efficient way to remove larger heat fluxes from a small cross-sectional area. In recent years, applications of carbon-based coatings for enhancing the pool boiling performance has become an attractive option due to very high thermal conductivities of carbon-based materials. Carbon-based coatings also assist in enhancing the morphological structures of the coatings. The focus of this work is to compare the morphologies, surface properties such as wettability and porosity, rendered by various coating methods and compare their resultant heat transfer coefficients (HTCs) and critical heat fluxes (CHFs). The underlying heat transfer mechanism for the test surfaces is evaluated based on the morphological features obtained from each of the coating methods which includes chemical vapor deposition (CVD), dip coating, screen printing, and electrodeposition. The surfaces are characterized by scanning electron microscope (SEM) and x-ray diffraction (XRD) spectroscopy. It was observed that carbon-based coatings formed a unique nanoscale and/or microscale geometries and structures which assisted in enhancing the morphology, porosity, and in turn the overall heat transfer performance.