Effects of Turbulent Dispersion on Water Droplet Impingement Based on Statistics Method

Research on the water droplet motion and impact on surface is the basis of aircraft icing prediction and design of ice protection system. First, a new computational method based on statistical theory was developed in the Euler–Lagrange framework to calculate the local water impingement coefficient on the surface, which could be used to study the effect of turbulent dispersion on the water droplet motion and impingement characteristics. Second, based on the RANS model for the air flow field, taking engine cone surface with or without slot as examples, the influence of turbulent dispersion on the water impingement coefficient on the surface was comparatively analyzed with the discrete random walk model. For the cone without film slot, turbulence causes a little impact on water droplet impingement. However, for the slotted cone, water droplet collection calculation must consider the effect of turbulence due to the stronger turbulence induced by the jet air. Further studies show that the effect is enhanced with the decrease of water droplet diameter. Finally, discussion about turbulent effects was proposed. This research about the influence of turbulent dispersion will be helpful to improve the accuracy of the water droplet impingement calculation for some complex geometries.