Two-phase flow characteristics across sudden expansion in small rectangular channels

The influence of abruptly variable cross-section on oil core eccentricity and flow characteristics during viscous oil-water horizontal flow

“…In the last decades (beginning with development of nuclear plants), there have been a large number of research studies on two-phase gas-liquid flows in the presence of singularities, e.g. sudden contraction and expansion, see for instance, Wadle (1989), Attou and Bolle (1997), Chen et al (2007) and Chen et al (2009). However, a complete and general characterization of the fluid dynamics downstream the geometric singularity is far from being achieved.…”

Air-water two-phase flow through U-bend, sudden expansion and sudden contraction in rectangular mini-channels

“…Figures 10(a)-(c) compare two-phase singularity pressure drop between experiment and calculation, respectively by Chisholm's correlation [9] for the Ubend, Schmidt and Friedel's correlation [14] for the sudden contraction and Wadle's correlation [18] for the sudden expansion, which showed the best predictions for the present data. Most of the data in 0.5 < j L < 2.0 m/s are well -0.079 0.211 [14] Abdelall et al [15] 0.639 1.263 [15] Mini-channel Chen et al [16] 5.689 16.787 [16] Mini-channel (a) Chisholm [9] (b) Schmidt and Friedel [14] (c) Wadle [18] Figure 10: Comparison of two-phase singularity pressure drop between experiment and calculation.…”

“…Main parameters measured are frictional pressure drop, bubble velocity and void fraction in the straight channel sections, and pressure drops at U-bend, sudden expansion and sudden contraction. In the analysis, pressure drop data at the singularities are compared with the calculations by correlations in literatures for U-bend [5][6][7][8][9][10][11], sudden contraction [12][13][14][15][16] and sudden expansion [13,[17][18][19][20]. Results of the experiments and the analysis are described in the present paper.…”

Two-phase flow pressure change subject to sudden contraction in small rectangular channels

“…At an abrupt flow area change, eddy flow formed in the separation region which is a clear sign of the irreversibility for a large pressure loss. There had been some developed correlations applicable to the pressure change for the conventional tubes, however, very few investigations had reported this abrupt pressure change with respect to mini channels (Abdelall et al, 2005;Chen et al, 2007). Also, a detailed physical description of two-phase flow across the abrupt flow area change in smaller rectangular channels is still not available.…”

“…One of the most common arrangements is plate-fin compact heat exchanger using rectangular channels with hydraulic diameters less than 5 mm and mass flux less than 350 kg/m 2 s (Wambsganss et al, 1992). Also, flow in small rectangular channels is an integral part of CPU cold plate using the liquid cooling with or without phase change (Chen et al, 2007).…”