Ιδρυματικό Αποθετήριο
Πολυτεχνείο Κρήτης
Πολυτεχνείο Κρήτης
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| URI | http://purl.tuc.gr/dl/dias/8BF2C76D-9908-42F0-AFF0-5BC1868D0EBB | - |
| Αναγνωριστικό | https://doi.org/10.1016/j.expthermflusci.2019.05.015 | - |
| Αναγνωριστικό | https://www.sciencedirect.com/science/article/pii/S0894177718316224 | - |
| Γλώσσα | en | - |
| Μέγεθος | 14 pages | en |
| Τίτλος | Micro-grooved surfaces to enhance flow boiling in a macro-channel | en |
| Δημιουργός | Vlachou Maria C. | en |
| Δημιουργός | Efstathiou Charikleia | en |
| Δημιουργός | Ευσταθιου Χαρικλεια | el |
| Δημιουργός | Antoniadis Aristomenis | en |
| Δημιουργός | Αντωνιαδης Αριστομενης | el |
| Δημιουργός | Karapantsios Thodoris D. | en |
| Εκδότης | Elsevier | en |
| Περίληψη | The influence of the boiling surface morphology on subcooled flow boiling heat transfer is investigated. Flow boiling experiments are conducted in a macro-channel with water entering at 30 °C. The channel has an orthogonal cross-section (10x40 mm) with a short (length: 120 mm) one-sided heated wall. Experiments are performed at two flow directions, horizontal and vertical upward. The examined mass and heat fluxes range between 330–830 kg/m2s and 200–1000 kW/m2, respectively. Two copper boiling surfaces are manufactured by laser etching: one with micro-grooves parallel to the flow direction (surface #1) and one with micro-grooves perpendicular to the flow direction (surface #2). The grooves have the same width (420 μm) and depth (290 μm) but their length varies: 100 mm along the channel's length (surface #1) and 30 mm across the channel's width (surface #2). The presence of grooves yields ∼ 8% increase of heat exchange area in both surfaces. A smooth plain copper surface is employed as reference. Micro-grooves lead to boiling inception at lower wall superheats (−70% for horizontal and −30% for vertical channel inclination) and also enhance heat transfer coefficients (10–15% for horizontal and 5–7% for vertical channel inclination) compared to the smooth surface; this is for two reasons: (a) laser etching creates micro-scale-roughness inside the grooves, which provide more active bubble nucleation sites, and (b) the bottom of the grooves is hotter than the rest of the surface. As a result, many bubbles are generated inside the grooves, where they grow and coalescence with other bubbles at a greater extent than the rest of the boiling surface. The beneficial effect of the grooved surfaces is beyond the gain offered by the rise in surface area and it is seen mainly in the horizontal inclination, whereas it is less evident in the vertical inclination. This is comparable with the discrepancy observed between inclinations for the smooth boiling surface. | en |
| Τύπος | Peer-Reviewed Journal Publication | en |
| Τύπος | Δημοσίευση σε Περιοδικό με Κριτές | el |
| Άδεια Χρήσης | http://creativecommons.org/licenses/by/4.0/ | en |
| Ημερομηνία | 2020-04-07 | - |
| Ημερομηνία Δημοσίευσης | 2019 | - |
| Θεματική Κατηγορία | Bubble dynamic behavior | en |
| Θεματική Κατηγορία | Flow boiling incipience | en |
| Θεματική Κατηγορία | Heat transfer coefficient | en |
| Θεματική Κατηγορία | Laser etching | en |
| Θεματική Κατηγορία | Passive enhancement technique | en |
| Θεματική Κατηγορία | Surface treatment | en |
| Βιβλιογραφική Αναφορά | M.C. Vlachou, C. Efstathiou, A. Antoniadis and T.D. Karapantsios, "Micro-grooved surfaces to enhance flow boiling in a macro-channel," Exp. Therm. Fluid Sci., vol. 108, pp. 61-74, Nov. 2019. doi: 10.1016/j.expthermflusci.2019.05.015 | en |
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