The maximum spreading lengths in circumferential and axial directions when droplets impact on cylindrical surfaces

The maximum spreading length of liquid film after droplets impacting on cylindrical surfaces reflects one of the important aspects in the dynamic behaviors. In this paper, the parametric influence on the maximum spreading lengths in circumferential and axial directions, and the relationship between two maximum spreading lengths, were studied by the numerical simulation and theoretical analysis methods, respectively. The results show that, both of the apparent contact angle and Weber number have a crucial influence on the maximum spreading length of liquid film, but for the effect of cylinder diameter, when the cylinder diameter is much larger than the droplet's, the change of cylinder diameter does not affect the maximum spreading lengths in both directions significantly. In addition, an acceptable relationship between the maximum circumferential and axial spreading lengths has been obtained from the established theoretical analysis model. By comparison of the calculated results from the relationship with simulated and experimental data, the deviation is within ±25.8%.