3D Numerical Investigation of Surface Wettability Effects on Runback Water Flow Evolution on the Aero‑engine Rotating Spinners

The icing of areo-engine inlet components during flight can affect engine operational safety. Conventional hot-air anti-icing systems require a large amount of bleed air， which compromises engine performance. Consequently， low-energy anti/de-icing methods based on superhydrophobic surfaces have attracted widespread attention. Previous studies have demonstrated that for stationary components， superhydrophobic surfaces can significantly reduce anti-icing energy consumption by altering the flow behavior of runback water. However， for rotating inlet components of aero-engines， the effectiveness of superhydrophobic surfaces and the influence of surface wettability on the evolution of runback water flow remain unclear due to the effects of centrifugal and Coriolis forces. This study establishes a 3D liquid water flow simulation model using the volume of fluid （VOF） method to investigate the effects of rotational speed， airflow velocity， and surface wettability on the runback water flow behavior over the rotating spinner under dynamic rotation conditions. The results show that the rotational effects and surface wettability mutually reinforce one another. Specifically， increasing the rotational speed and contact angle can both enhance the flow velocity of liquid water and accelerate the breakup and rupture of liquid film， leading to the formation of rivulets， droplets， and subsequent detachment from the surface. A theoretical model based on force balance is proposed to describe the evolution of runback water flow， and the analysis reveals that as the rotational speed and contact angle increase， the water film is more likely to break up to form rivulets and beads， and the critical radius for droplet detachment from the surface decreases， making it easier removal from the surface.