The internal flow of a cross flow fan (CFF) is complex. Therefore, the design method for a CFF has not yet been established. In our CFF study, the authors measured the internal flow by particle tracking velocimetry using an experimental apparatus for water flow visualization. The pathline images photographed with a digital still camera were analyzed by the computer program developed by one of the authors to obtain velocity distributions. This measuring method was applicable to this study. The measured results were discussed from several points of view and useful information on the internal flow of the CFF was obtained.
