Effect of Coanda nozzle clearance on the flow characteristics of air amplifier

An air amplifier makes air flow increased by ejecting a small amount of air, which results in the Coanda effect: A tendency of keeping fluids attached to an adjacent surface while the air flow is passing along the wall boundary. In this paper, the flow characteristics of an air amplifier were investigated with various flow and geometrical conditions. In particular, various values of the Coanda nozzle clearance (δ = 0.1, 0.2, 0.3, 0.4, and 0.5 mm), diffuser angles (α = 15°, 20°, 25°), and pressure conditions (p_c = 0.1, 0.2, 0.3, and 0.4 MPa) were considered. Numerical analysis was performed using a commercial CFD code, ANSYS CFX 14.5 with the shear stress transport (SST) turbulent model. The results of pressure and velocity distributions were graphically depicted with various operating conditions.