Buoyancy effects in steeply inclined air-water bubbly shear flow in a rectangular channel
We report measurements of two-dimensional (B/D = 5) fully turbulent and developed duct flows (overall length/depth, L/D = 60; D-based Reynolds number Re > 104) for inclinations to 30° from vertical at low voidages (< 5 % sectional average) representative of disperse regime using tap water bubb...
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| Format: | Article |
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Maik Nauka-Interperiodica Publishing
2015
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| Online Access: | http://ir.unimas.my/id/eprint/12702/ |
| _version_ | 1848837254969032704 |
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| author | Sanaullah, K. Arshad, Mehmood Khan, A. Chughtai, I.R |
| author_facet | Sanaullah, K. Arshad, Mehmood Khan, A. Chughtai, I.R |
| author_sort | Sanaullah, K. |
| building | UNIMAS Institutional Repository |
| collection | Online Access |
| description | We report measurements of two-dimensional (B/D = 5) fully turbulent and developed duct flows (overall length/depth, L/D = 60; D-based Reynolds number Re > 104) for inclinations to 30° from vertical at low voidages (< 5 % sectional average) representative of disperse regime using tap water bubbles (4–6 mm) and smaller bubbles (2 mm) stabilised in ionic solution. Pitot and static probe instrumentation, primitive but validated, provided adequate (10 % local value) discrimination of main aspects of the mean velocity and voidage profiles at representative streamwise station i.e L/D = 40. Our results can be divided into three categories of behaviour. For vertical flow (0°) the evidence is inconclusive as to whether bubbles are preferentially trapped within the wall-layer as found in some, may be most earlier experimental works. Thus, the 4-mm bubbles showed indication of voidage retention but the 2-mm bubbles did not. For nearly vertical flow (5°) there was pronounced profiling of voidage especially with 4-mm bubbles but the transverse transport was not suppressed sufficiently to induce any obvious layering. In this context, we also refer to similarities with previous work on one-phase vertical and nearly vertical mixed convection flows displaying buoyancy inhibited mean shear turbulence. However, with inclined flow (10+ degrees) a distinctively layered pattern was invariably manifested in which voidage confinement increased with increasing inclination. In this paper we address flow behavior at near vertical conditions. Eulerian, mixed and VOF models were used to compute voidage and mean velocity profiles. |
| first_indexed | 2025-11-15T06:36:45Z |
| format | Article |
| id | unimas-12702 |
| institution | Universiti Malaysia Sarawak |
| institution_category | Local University |
| last_indexed | 2025-11-15T06:36:45Z |
| publishDate | 2015 |
| publisher | Maik Nauka-Interperiodica Publishing |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | unimas-127022016-07-28T02:14:58Z http://ir.unimas.my/id/eprint/12702/ Buoyancy effects in steeply inclined air-water bubbly shear flow in a rectangular channel Sanaullah, K. Arshad, Mehmood Khan, A. Chughtai, I.R TP Chemical technology We report measurements of two-dimensional (B/D = 5) fully turbulent and developed duct flows (overall length/depth, L/D = 60; D-based Reynolds number Re > 104) for inclinations to 30° from vertical at low voidages (< 5 % sectional average) representative of disperse regime using tap water bubbles (4–6 mm) and smaller bubbles (2 mm) stabilised in ionic solution. Pitot and static probe instrumentation, primitive but validated, provided adequate (10 % local value) discrimination of main aspects of the mean velocity and voidage profiles at representative streamwise station i.e L/D = 40. Our results can be divided into three categories of behaviour. For vertical flow (0°) the evidence is inconclusive as to whether bubbles are preferentially trapped within the wall-layer as found in some, may be most earlier experimental works. Thus, the 4-mm bubbles showed indication of voidage retention but the 2-mm bubbles did not. For nearly vertical flow (5°) there was pronounced profiling of voidage especially with 4-mm bubbles but the transverse transport was not suppressed sufficiently to induce any obvious layering. In this context, we also refer to similarities with previous work on one-phase vertical and nearly vertical mixed convection flows displaying buoyancy inhibited mean shear turbulence. However, with inclined flow (10+ degrees) a distinctively layered pattern was invariably manifested in which voidage confinement increased with increasing inclination. In this paper we address flow behavior at near vertical conditions. Eulerian, mixed and VOF models were used to compute voidage and mean velocity profiles. Maik Nauka-Interperiodica Publishing 2015 Article PeerReviewed Sanaullah, K. and Arshad, Mehmood and Khan, A. and Chughtai, I.R (2015) Buoyancy effects in steeply inclined air-water bubbly shear flow in a rectangular channel. Thermophysics and Aeromechanics, 22 (4). pp. 463-473. ISSN 0869-8643 https://www.scopus.com/record/display.uri?eid=2-s2.0-84944064004&origin=inward&txGid=0 DOI: 10.1134/S0869864315040071 |
| spellingShingle | TP Chemical technology Sanaullah, K. Arshad, Mehmood Khan, A. Chughtai, I.R Buoyancy effects in steeply inclined air-water bubbly shear flow in a rectangular channel |
| title | Buoyancy effects in steeply inclined air-water bubbly shear flow in a rectangular channel |
| title_full | Buoyancy effects in steeply inclined air-water bubbly shear flow in a rectangular channel |
| title_fullStr | Buoyancy effects in steeply inclined air-water bubbly shear flow in a rectangular channel |
| title_full_unstemmed | Buoyancy effects in steeply inclined air-water bubbly shear flow in a rectangular channel |
| title_short | Buoyancy effects in steeply inclined air-water bubbly shear flow in a rectangular channel |
| title_sort | buoyancy effects in steeply inclined air-water bubbly shear flow in a rectangular channel |
| topic | TP Chemical technology |
| url | http://ir.unimas.my/id/eprint/12702/ http://ir.unimas.my/id/eprint/12702/ http://ir.unimas.my/id/eprint/12702/ |