| Title |
Air-water Countercurrent Flow Limitation in Narrow Rectangular Channels |
| Keywords |
대향류 2상유동 ; 유동한계 ; 협소사각유로 Countercurrent two-phase flow ; Flow limitation ; Narrow rectangular channel |
| Abstract |
An experimental study on the countercurrent two-phase flow in narrow rec-tangular channels has been performed. Countercurrent flow limitation (CCFL) was investigated using air and water in 760mm long, 100mm wide, vertical test sections with 1 and 3mm channel gaps. Tests were systematically performed with downward liquid superficial velocities and upward gas velocities covering 0 to 0.125 and 0 to 3.5m/s ranges, respectively. As the gap width of rectangular channel increased the CCFL water superficial velocity decreased for the given air superficial velocity. Slight increase of the air superficial velocity resulted in the abrupt decrease of water velocity when jg=2∼4m/s. The critical superficial velocity of air, at which the downward flow of water was no longer allowed, also decreased with the increase of gap width. The experimental results were compared with the previous correlations, which were mainly for round tubes, and the qualitative trends were found to be partially acceptable. However the quantitative discrepancies were hardly neglected. New correlation of CCFL was developed and showed good agreement with the experimental data. |