Liquid film behavior upon an oblique jet impinging on a solid wall

This work numerically explores the effect of different Reynolds numbers, inclination angles, and wall surface roughness on liquid film behaviors upon a jet impinging on a solid wall. The Volume of Fluid approach with contact angle correction, in conjunction with surface roughness estimation based on boundary layer flow, was applied. A new model for predicting the geometry of the liquid film with full consideration of flow characteristics and jet conditions was proposed. Results show that the present model predicts the maximum liquid film width, the starting point of the liquid film, and the liquid film morphology with improved accuracy. With an increase in jet Reynolds number from 1600 to 3600, the maximum width of the liquid film increases from r/D = 11.8 to 16.5, and the maximum thickness increases from h/D = 1.2 to 1.9. The pressure coefficient shows little change, while the skin friction coefficient decreases with higher Reynolds number. The variation of α from 45° to 75° shows a weak influence on the film thickness distribution in the thin layer zone. Increasing the injection angle results in a downward shift (r/D = 0.8) of the maximum pressure coefficient. The maximum pressure coefficient increases by about 25%, while the maximum skin friction coefficient increases by about 55% with a higher injection angle. With an increase in surface roughness, the maximum width of the liquid film increases about 10%, the maximum pressure coefficient by about 20%, and the maximum skin friction coefficient by about 26%.