Enhancement of Particle Removal Performance of High-speed Air Jet by Setting Obstacle in Jet Flow

Surface cleaning using high-speed air jet can be applied to cleaning of an object with concavo-convex shape. In such cases, the distance between the air jet nozzle and the surface becomes on the order of cm. An increase in the distance causes a decrease of the air velocity at the surface resulting in deterioration of the particle removal performance of the air jet. Therefore, a method to enhance removal efficiency is required. In this study, we investigated two methods for the enhancement of removal efficiency: one is to set a wire in the air flow and the other is to set two cylindrical rods. Although the wire set at the center of the jet flow deteriorates the removal efficiency, experimental results imply that the wire has a positive effect on the efficiency when it is set at a position where it does not interfere with the main flow of the jet. On the other hand, when two cylindrical rods are set at a theoretical periphery of the air jet, it shows clearly an enhancement in removal efficiency. This fact implies that the removal efficiency can be enhanced by controlling flow fluctuation by means of setting an obstacle.