Parametric analysis of interfacial friction factor for liquid film dynamics sheared by turbulent gas flow

Water droplet impingement on a low-pressure steam turbine blade causing erosion has been recognized as a crucial issue. It is essential to elucidate a comprehensive droplet detachment mechanism, not only from the trailing edge but also from the liquid film surface. In the present paper, we investigate the influence of interfacial friction factor against liquid film dynamics on a wall sheared by a turbulent gas flow, including the liquid film thickness, liquid film velocity and entrained droplet detached from liquid surface for both pipe flow and plate flow conditions. We conduct the analyses by using a liquid film dynamics model, recently established, considering the three-dimensional destabilized waves and droplet entrainment from the liquid surface. As a result, the film thickness and velocity greatly depends on the interfacial friction factor. Interestingly, the rate of entrained droplet to initial liquid film has a minimum value when the interfacial friction factor equals to the inverse of the liquid film Reynolds number, while the remaining liquid film flow rate becomes maximum.