The cross-flow fan discussed here is incorporated into an air conditioner that has the inlet on top and does not have apertures in front, that is, it has a flat front panel. In order to get fundamental characteristics of the cross-flow fan, a flow measurement system by laser doppler velocimeter (LDV), which can obtain both velocity data and turbulence data, was adopted. The LDV used in this study is a two-colour, four-beam system, which is suitable for measuring unsteady flow such as the flow in a cross-flow fan. Describes the variation of the internal flow in the cross-flow fan and the vortex movement that occurs when the position of the flat front panel, or the distance between the tongue and the impeller, or the shape of the suction region is changed.

KEYWORDS: air flow, measuring, laser doppler anemometers, cross flow fans, unit air conditioners, speed, properties, turbulent flow, anemometers.