Numerical sumulation on optimization design of contraction section in icing wind tunnel based on droplet trajectory

Performance of icing wind tunnel's contraction section was investigated by numerical simulation.For several typical wall contours were provided by former researchers,the flow field calculation using simplified 2-D (two-dimensional)model was performed,and the pressures along the centerline and the velocity distribution at the test section entrance were obtained.The numerical simulation results show that all contraction curves can prevent the separation of boundary layers,and the difference of fluid dynamics parameters is negligible except for cubic curve and fifth power curve(x_m=0.4) which can't provide a specified degree of uniformity.Then droplet trajectory was studied by numerical simulation when different diameter water-liquid that the droplets were released.The numerical results state droplet accretion using Witozinsky curve is less compared with that designed by other curves.By comparing of several contraction curves' effect on flow field and droplet trajectory,it can be concluded that convergent section designed by fifth power curve (x_m=0.5) has higher efficiency.