Abstract
In the present study, experiments were performed to observe vapor-liquid two-phase flow of a refrigerant R 410A in a horizontal small triangular channel with a glass tube and a high speed camera. The hydraulic diameter of glass tube was 0.82 mm. Based on the observation, flow patterns were classified into several flow regimes, and the effect of channel arrangement against gravity direction on the flow pattern was clarified. Furthermore, the effects of cross-sectional shape and flow direction were made clear by comparing with data of upward and downward flow in a triangular channel and horizontal flow in circular and rectangular channels previously obtained.