Abstract: For a abnormal noise problem in cross-flow air duct of a portable air conditioner. Based on the CFD numerical simulation and experimental method, the aerodynamic characteristics and the influence of abnormal noise of cross-flow duct are analyzed. The abnormal nosie problem of the portable air conditioner is caused by the air flow in the gap between two sides of the blades and the chassis, which interferes the main flow and increases turbulence noise, resulting in the abnormal noise and unstable wind speed. The problem of abnormal noise is eliminated by modifing the design of air duct curve, which controlled the distribution of eccentric vortex and the entrainment area of eccentric vortex is offset upward, which increases the flow area of the cross-flow fan. It provides a solution for the abnormal sound of the subsequent cross-flow air duct. It provides a solution for the abnormal noise of the cross-flow air duct.

Key words: Cross-flow duct, Numerical simulation, Aerodynamic performance, Abnormal noise, Eccentric vortex