Droplet motion on non-smooth solid surface

Liquid dripping in a packed bed of coke in a blast furnace decreases the gas permeability and production stability. Enhancing the liquid flow is desirable to increase the productivity of the blast furnace process. The wettability between the liquid and coke affects the dripping behavior. In present study, the contact angle of a moving droplet on a non-smooth solid surface was investigated considering dripping slag and pig iron droplets in a packed bed of coke. The advancing and receding contact angles of water and mercury on a substrate were measured at room temperature while controlling the wettability and roughness. The angles between the cut surface of the coke and water or mercury were also measured. The roughness of the solid surface affected the movement of the adhering droplets, but the effect of the roughness was significantly altered by the wettability. It was found that the resistance to movement of the liquid increased and decreased under good and poor wettability conditions, respectively. Because the wettability of the liquid phase in the blast furnace changed depending on the temperature and composition of molten slag or iron, the force on a liquid droplet from the coke surface changed depending on the position and composition of the hot metal and molten slag in the coke bed.