Flow pattern and boiling heat transfer of CO2 in horizontal small-bore tubes

Traveling void wave in horizontal two-phase flow

“…In addition, the slug-annular flow in the simulation penetrates into the predicted annular flow region, which is quite similar to the experimental observation. The slug flow occupying low mass flux region of the simulation has not been observed in the experiment due to the limitation of the pump performance, while experimental data at 5.0 MPa suggest an availability of the present model [19] for slug flow as well. Detailed discussion on the comparison with the existing criteria may be found elsewhere [19].…”

“…From this context, a mist flow is quite different in the arrangement of phases from the pre-determined hypothetical bubble system shown in Fig. 2, and thus out of scope of the present model, although mist flow was observed in the experiment at very high quality at lower pressure, 5.0 MPa [18,19].…”

“…Aiming at the verification of the present horizontal flow model, the simulation condition and the system configurations are selected as shown in Table 1 so that the flow pattern maps are compared with the experiment by the authors [18,19].…”

“…Operating pressure was in the range 4.0-6.7 MPa, mass flux was ranging from 200 to 700 kg/m 2 s, and vapor quality 0.05-0.9. Detailed description may be found elsewhere [18,19].…”

“…12 together with the experimental result (upper column) [18,19]. In these flow pattern maps, so far proposed flow pattern transition criteria are also drawn for reference: solid lines by Cheng et al [21] developed for CO 2 with ordinary tube size (tube diameters from 0.6 to 10 mm), and the dashed lines by Revellin and Thome [22] for micro-channels, where symbol ''IB" denotes isolated bubble regime, ''CB" coalescing bubble regime, and ''A" annular flow regime.…”