Effect of Corrosion and Wall Textures on Wettability and Heat Flux at Non-Isothermal Conditions

Abstract

The corrosion behavior, evaporation and heat transfer of aluminum alloy during droplet evaporation of an aggressive solution of NaCl and hydrogen peroxide in water have been studied experimentally. To date, the effect of corrosion on the evaporation and heat transfer of droplet salt solutions on textured surfaces remains insufficiently explored. The corrosion resistance of the material and the contact angle increase with an increase in the number of laser penetrations after laser texturing. Studies conducted using an electron microscope and Energy-Dispersive X-ray Spectroscopy (EDS) mapping show that the maximum amount of adsorbed hydrocarbon impurities falls on areas with a large number of pits. In the process of metal corrosion, wettability and heat transfer change. In spite of the fact that laser exposure significantly increases the corrosion resistance, the wettability of the wall changes significantly due to corrosion. The wetted diameter of a droplet changes over time, which leads to an increase in the evaporation rate and heat flux. The heat flux during evaporation of a droplet on a heated wall depends on the water droplet diameter, the texture of the wall and the corrosion resistance.