Investigation of ice detachment by a liquid jet on various submerged surfaces for the development of ice slurry generators without mechanical scraping

Abstract

Ice slurry is an alternative method to reduce the quantity and emission of greenhouse refrigerants, as well as control electrical energy consumption. However, the production of ice slurry requires the use of scraped-surface generators, which are costly to maintain and consume high mechanical energy. Therefore, studying the icephobic behavior of surfaces is of interest to significantly reduce ice adhesion and facilitate detachment without the need for mechanical scrapers. This study focuses on the growth, adhesion, and detachment phenomena of ice by liquid jets on different types of surfaces (hydrophilic, hydrophobic, and superhydrophobic) immersed in a 10 wt% ethanol/water mixture. A liquid jet is used to detach the ice layer from the surfaces, with a velocity ranging from 0 to 2.87 m s−1, and the surface temperature varies from 25 °C to approximately –9 °C. The results show that ice adheres less to hydrophilic and hydrophobic surfaces compared to superhydrophobic surfaces. The use of PTFE-treated aluminum surfaces (hydrophobic) reduces the required flow velocity to detach the ice layer by half compared to untreated aluminum surfaces (hydrophilic). An ANSYS® Fluent numerical model was developed to simulate the evolution of turbulent velocities of immersed liquid jets, and a semi-empirical model was designed to estimate the detachment forces of soft ice from hydrophilic surfaces (untreated aluminum). Two types of ice detachment from surfaces were identified: adhesive detachment and cohesive detachment.