Characteristics of heat transfer in impinging jets by control of vortex pairing

Hyung Hee Cho, C. H. Lee, Y. S. Kim

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

The present study is conducted experimentally to obtain heat transfer characteristics on the impingement surface for controlled jets. Counterflowing or coflowing stream around the jet periphery is used to control the jet at the nozzle lip. The characteristics of flow and heat transfer are studied on two different jet nozzle exit flow conditions, including a fully developed turbulent tube flow and an uniform velocity distribution flow. The experiments are carried out for nozzle-to-plate distances of 2 to 8 nozzle diameters, jet Reynolds numbers in the range of 10,000 to 70,000, and main and secondary flow velocity ratios, R=ΔU/2Ū, of 0.45 to 1.86. The secondary counter- and co-flows change the flow instability conditions in the shear layers resulting in changes of heat transfer on the impingement surface. For secondary counterflows, heat transfer on the impingement surface is changed little for the small nozzle-to-plate distance of H/D=2, but is enhanced on the stagnation region with reduction on the secondary peak region for H/D=4. Augmentation of heat transfer on the stagnation region increases with increasing jet Reynolds numbers. For secondary coflows, the jet potential core extends far downstream due to inhibited development of the vortices, but the heat transfer is reduced significantly and the secondary peak appears downstream with increasing blowing rates.

Original languageEnglish
Title of host publicationHeat Transfer; Electric Power; Industrial and Cogeneration
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791878651
DOIs
Publication statusPublished - 1998 Jan 1
EventASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition, GT 1998 - Stockholm, Sweden
Duration: 1998 Jun 21998 Jun 5

Publication series

NameProceedings of the ASME Turbo Expo
Volume4

Other

OtherASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition, GT 1998
CountrySweden
CityStockholm
Period98/6/298/6/5

Fingerprint

Vortex flow
Heat transfer
Nozzles
Reynolds number
Secondary flow
Pipe flow
Blow molding
Velocity distribution
Flow velocity
Experiments

All Science Journal Classification (ASJC) codes

  • Engineering(all)

Cite this

Cho, H. H., Lee, C. H., & Kim, Y. S. (1998). Characteristics of heat transfer in impinging jets by control of vortex pairing. In Heat Transfer; Electric Power; Industrial and Cogeneration (Proceedings of the ASME Turbo Expo; Vol. 4). American Society of Mechanical Engineers (ASME). https://doi.org/10.1115/98-GT-276
Cho, Hyung Hee ; Lee, C. H. ; Kim, Y. S. / Characteristics of heat transfer in impinging jets by control of vortex pairing. Heat Transfer; Electric Power; Industrial and Cogeneration. American Society of Mechanical Engineers (ASME), 1998. (Proceedings of the ASME Turbo Expo).
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Cho, HH, Lee, CH & Kim, YS 1998, Characteristics of heat transfer in impinging jets by control of vortex pairing. in Heat Transfer; Electric Power; Industrial and Cogeneration. Proceedings of the ASME Turbo Expo, vol. 4, American Society of Mechanical Engineers (ASME), ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition, GT 1998, Stockholm, Sweden, 98/6/2. https://doi.org/10.1115/98-GT-276

Characteristics of heat transfer in impinging jets by control of vortex pairing. / Cho, Hyung Hee; Lee, C. H.; Kim, Y. S.

Heat Transfer; Electric Power; Industrial and Cogeneration. American Society of Mechanical Engineers (ASME), 1998. (Proceedings of the ASME Turbo Expo; Vol. 4).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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AB - The present study is conducted experimentally to obtain heat transfer characteristics on the impingement surface for controlled jets. Counterflowing or coflowing stream around the jet periphery is used to control the jet at the nozzle lip. The characteristics of flow and heat transfer are studied on two different jet nozzle exit flow conditions, including a fully developed turbulent tube flow and an uniform velocity distribution flow. The experiments are carried out for nozzle-to-plate distances of 2 to 8 nozzle diameters, jet Reynolds numbers in the range of 10,000 to 70,000, and main and secondary flow velocity ratios, R=ΔU/2Ū, of 0.45 to 1.86. The secondary counter- and co-flows change the flow instability conditions in the shear layers resulting in changes of heat transfer on the impingement surface. For secondary counterflows, heat transfer on the impingement surface is changed little for the small nozzle-to-plate distance of H/D=2, but is enhanced on the stagnation region with reduction on the secondary peak region for H/D=4. Augmentation of heat transfer on the stagnation region increases with increasing jet Reynolds numbers. For secondary coflows, the jet potential core extends far downstream due to inhibited development of the vortices, but the heat transfer is reduced significantly and the secondary peak appears downstream with increasing blowing rates.

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Cho HH, Lee CH, Kim YS. Characteristics of heat transfer in impinging jets by control of vortex pairing. In Heat Transfer; Electric Power; Industrial and Cogeneration. American Society of Mechanical Engineers (ASME). 1998. (Proceedings of the ASME Turbo Expo). https://doi.org/10.1115/98-GT-276