Abstract: Under complex operating conditions, the stability of the air flow of the cross-flow duct directly influences the operational efficiency of wall-mounted air conditioners and the comfort for users. To investigate these influences, the flow field under different inlet resistance conditions were analyzed using numerical simulations. It was found that excessive resistance leads to eccentric vortex disturbances in the cross-flow duct, resulting in periodic backflow and fluctuating noise. Based on the mechanism, a gradually varying volute tongue was employed. In addition, the optimal radius and length of the volute tongue were determined experimentally, which finally enhances the fluid resistance performance of the duct of cross flow fan.

Key words: Wall-mounted air conditioner, Cross flow fan duct, High fluid resistance, Structure of volute throat