Open AccessHeat transfer enhancement by surface vortex generators. New basic mechanisms and industrial technologies
Author(s) -
С. А. Исаев,
Э. Е. Сон,
A. I. Leontiev,
И. А. Попов,
Д. В. Никущенко
Publication year - 2020
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1683/2/022084
Subject(s) - dimple , heat transfer enhancement , heat transfer , vortex generator , vortex , mechanics , radius , turbulence , nusselt number , materials science , thermal , flow (mathematics) , channel (broadcasting) , geometry , heat transfer coefficient , optics , thermodynamics , composite material , physics , reynolds number , mathematics , electrical engineering , engineering , computer security , computer science
New energy effective surfaces structured by vortex generators – inclined oval-trench dimples (OTDs) – and the controlling physical mechanisms of heat transfer enhancement are explored. The narrow 7 × 1 channel with a package of one-row OTDs at Re=10 4 .is considered. Turbulent heat transfer is studied at the channel length where the flow is steady. The OTD width is 1, its depth is 0.3, its length is 7 0.3, and its dimple step is 6. The rounding radius of the dimple edge is 0.2. The influence of the OTD inclination angle θ on the mechanisms of separated flow intensification and heat transfer enhancement in the dimple is analyzed when θ is varied from 42° to 55.5°. The optimal angle θ of order 53° is revealed, at which the relative thermal performance is close to 70% for the heated wall with a very loose packing of dimples equal to 0.235. The optimal angle θ, at which the highest thermal and hydraulic performance (THP=0.175) has been achieved, appears to be close to 47°. The maximum local value of the 4.5–5-fold relative heat transfer growth coincides with that of static pressure in the separated flow zone on the section, where relative friction grows, after it has reached its minimum value up to -4.5.