On the Behavior of Water Droplets When Moving Onto Blade Surface in a Wet Compression Transonic Compressor

The process of wet compression in an axial compressor is an intricate two-phase flow involving not only heat and mass transfer processes but also droplet breakup and even formation of discontinuous water film on the blade surface and then breaking into droplets. In this paper, the droplet-wall interactions are analyzed using the theory of spray wall impingement through two computational models for an isolated transonic compressor rotor (NASA rotor 37). Model 1, representing spread phenomenon, assumes that all droplets impacting on the blade are trapped in the water film and subsequently released from its trailing edge and enter the wake region with an equivalent mass flow but bigger in diameter and smaller in number. Whereas, the model 2, representing splashing phenomenon, assumes that upon impacting on the blade, the droplets will breakup into many smaller ones. The three-dimensional flow simulation results of these two models are analyzed and compared in this paper.