Numerical investigation on wetting behavior and heat transfer characteristics of film flow on the smooth and orthogonal wave plates

Three-dimensional gravity-driven film flowing on a smooth plate and three orthogonal wave plates are studied numerically by using the Finite Volume Method in this paper. The volume of fluid (VOF) model is applied to simulate the gas-liquid interface. The existing experimental data of water film flowing down the inclined smooth plate are employed to verify the reliability of the numerical implementation. Results obtained indicate that different fluids have different wetting characteristics even at the same Reynolds number. The wetting area on the orthogonal wave plates is less than that of the smooth plate at $\mathbf{Re}\geq 163$, especially for wave plates with higher wave depth. The influence of the plate wave depth is more noteworthy than that of the plate wavelength. For the wave plates, the wetting ratio decreases with the growing of inclination angles, but the effect can be neglect when Re is larger than 300. The local heat transfer coefficients of the smooth plate drop along the flow length, and the wave plate can enhance the heat transfer performance at a certain range of depth-length ratio (Rt).