2024-03-29T05:00:44Z
https://nagoya.repo.nii.ac.jp/oai
oai:nagoya.repo.nii.ac.jp:00025743
2023-01-16T04:15:43Z
320:321:322
Enhancement and suppression of mixing and diffusion in an axisymmetric jet by half delta-wing tabs
Ito, Y.
Miura, K.
Sakai, Y.
Iwano, K.
open access
© 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Turbulence
Jet control
Tabs
Diffusion
Entrainment
Mixing
Effects of half delta-wing tabs on mixing and diffusion in an axisymmetric jet are experimentally investigated. The tabs are installed at the jet exit circumferentially with an equal interval. The number of the tab is varied from 1 to 6. The jet Reynolds number is set to 20,000. Instantaneous streamwise and radial (vertical or horizontal) velocities and temperature are mainly measured by a composite probe which consists of an X-type hot-wire and an I-type cold-wire. The results show that mixing with the ambient fluid is more enhanced with increasing the number of the tab near the jet exit. However, in the downstream region, it is suppressed in the cases with 4, 5, and 6 tabs and most suppressed in the case with 6 tabs, while it is most enhanced in the case with 3 tabs. The analysis based on the mean velocity distribution indicates that, although the spatially-averaged entrainment velocity is basically decreased by the tabs, the mixing and entrainment can be enhanced when the entrainment area is significantly increased. Thermal diffusion is more enhanced with increasing the number of the tab near the jet exit but, in the downstream region, it is equivalent or suppressed in the cases with the tabs. These results are caused by the mixed effects of the tabs: enhancement of not only mixing and diffusion but also the energy dissipation. The present study suggests that it is feasible to both promote and suppress mixing of the jet by the half delta-wing tabs, and directional characteristics of the jet diffusion can be controlled by optimizing configuration of the tabs.
ファイル公開:2020/03/01
Elsevier
2018-03-01
eng
journal article
AM
http://hdl.handle.net/2237/00027948
https://nagoya.repo.nii.ac.jp/records/25743
https://doi.org/10.1016/j.ijheatmasstransfer.2017.11.053
00179310
International Journal of Heat and Mass Transfer
118
1218
1230
https://nagoya.repo.nii.ac.jp/record/25743/files/manuscript.pdf
application/pdf
3.6 MB
2020-03-01