Computational Fluid Dynamic (CFD) Simulation of Droplet Impact Behavior on Rough Surface

Coating ofurea is a recent interest in agriculture which still needs a lot ofresearch to increase the efficiency and effectiveness. Controlled-released urea (CRU) functions according to nitrogen demand pattern ofthe particular plant. Research on the droplet impact is performed to help in the prediction of the impingement behavior of these droplets for urea coating. However most of the studies and researches on this area currently focusing on a flat, smooth surface. Therefore this research is conducted to study the behavior of droplet impact on flat rough surface of different texture with
various impact velocities. This project is intended to simulate the droplet impact behavior on rough surfaces using computational fluid dynamics (CFD) 2- dimensional (2D) modeling based on the volume of fluid (VOF) approach by means of ANSYS FLUENT software. The liquid used as droplet is water and simulated at impact velocity of 3.0 m/s, 1.5 m/s and 0.5 m/s on roughness texture of 'triangle', 'square', 'curve' as well as smooth surface made of aluminum. Droplet spreading behavior of water droplet on surface of urea is successfully simulated using ANSYS FLUENT. In relation to coating coverage on the urea surface, the 'triangle' surface and 'curve' surface resembles closely to uneven surface of urea. To have 'square' surface is almost unlikely. Therefore it can be said that from the simulation, to have the best coating, low velocity of spray should be used to coat the urea which approximately around 0.5 m/s. Besides that, from the simulation result, the coating will be the best if the urea surface has the 'triangle' texture.