Effects of wakes on blade endwall heat transfer in high turbulence intensity

Sehjin Park, Ho Seong Sohn, Hyung Hee Cho, Hee Koo Moon, Yang Seok Han, Osamu Ueda

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

Abstract

Different types of vortices, such as horseshoe vortex, passage vortex, corner vortex, cause high heat transfer distributions and complex heat transfer characteristics at the endwall of turbine blades. In addition, the endwall heat transfer is also affected when the main flow is highly turbulent and wakes are generated by the trailing edge of the vane. Detailed heat transfer measurements are necessary to protect the blades under harsh and complex flow conditions. Therefore, this study investigated the heat transfer characteristics on the blade endwall under flow conditions that simulate high turbulence intensity of the main flow and the generation of wakes by the trailing edge of the vane. The endwall heat transfer was measured using the naphthalene sublimation method. A turbulence generating grid was installed in a linear cascade to simulate the main flow with high turbulence intensity and a wake generator with a rod bundle was used to simulate the wakes generated by the trailing edge of the vane. In the case of high turbulence intensity without wakes, the main flow with high turbulence intensity (Turbulence intensity, T.I = 7.5%) had little impact on the effect of the horseshoe vortex and passage vortex on the heat transfer characteristics. However, increasing turbulence caused the endwall heat transfer to decrease near the pressure side of the blade and increase near the suction side of the blade. On the other hand, the wakes resulted in heat transfer characteristics similar to high turbulence intensity, but decreased heat transfer by horseshoe vortex and passage vortex. The endwall heat transfer distributions were similar regardless of the turbulence intensity (T.I = 1.2%, 7.5%) in the cases with wakes (Rod passing Strouhal number, S = 0.3). This means that the flow condition of S = 0.3 has a more significant influence on the endwall heat transfer than that of T.I = 7.5%.

Original languageEnglish
Title of host publicationHeat Transfer
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791858646
DOIs
Publication statusPublished - 2019 Jan 1
EventASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition, GT 2019 - Phoenix, United States
Duration: 2019 Jun 172019 Jun 21

Publication series

NameProceedings of the ASME Turbo Expo
Volume5A-2019

Conference

ConferenceASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition, GT 2019
CountryUnited States
CityPhoenix
Period19/6/1719/6/21

Fingerprint

Turbulence
Heat transfer
Vortex flow
Strouhal number
Cascades (fluid mechanics)
Sublimation
Naphthalene
Turbomachine blades
Turbines

All Science Journal Classification (ASJC) codes

  • Engineering(all)

Cite this

Park, S., Sohn, H. S., Cho, H. H., Moon, H. K., Han, Y. S., & Ueda, O. (2019). Effects of wakes on blade endwall heat transfer in high turbulence intensity. In Heat Transfer (Proceedings of the ASME Turbo Expo; Vol. 5A-2019). American Society of Mechanical Engineers (ASME). https://doi.org/10.1115/GT2019-91493
Park, Sehjin ; Sohn, Ho Seong ; Cho, Hyung Hee ; Moon, Hee Koo ; Han, Yang Seok ; Ueda, Osamu. / Effects of wakes on blade endwall heat transfer in high turbulence intensity. Heat Transfer. American Society of Mechanical Engineers (ASME), 2019. (Proceedings of the ASME Turbo Expo).
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abstract = "Different types of vortices, such as horseshoe vortex, passage vortex, corner vortex, cause high heat transfer distributions and complex heat transfer characteristics at the endwall of turbine blades. In addition, the endwall heat transfer is also affected when the main flow is highly turbulent and wakes are generated by the trailing edge of the vane. Detailed heat transfer measurements are necessary to protect the blades under harsh and complex flow conditions. Therefore, this study investigated the heat transfer characteristics on the blade endwall under flow conditions that simulate high turbulence intensity of the main flow and the generation of wakes by the trailing edge of the vane. The endwall heat transfer was measured using the naphthalene sublimation method. A turbulence generating grid was installed in a linear cascade to simulate the main flow with high turbulence intensity and a wake generator with a rod bundle was used to simulate the wakes generated by the trailing edge of the vane. In the case of high turbulence intensity without wakes, the main flow with high turbulence intensity (Turbulence intensity, T.I = 7.5{\%}) had little impact on the effect of the horseshoe vortex and passage vortex on the heat transfer characteristics. However, increasing turbulence caused the endwall heat transfer to decrease near the pressure side of the blade and increase near the suction side of the blade. On the other hand, the wakes resulted in heat transfer characteristics similar to high turbulence intensity, but decreased heat transfer by horseshoe vortex and passage vortex. The endwall heat transfer distributions were similar regardless of the turbulence intensity (T.I = 1.2{\%}, 7.5{\%}) in the cases with wakes (Rod passing Strouhal number, S = 0.3). This means that the flow condition of S = 0.3 has a more significant influence on the endwall heat transfer than that of T.I = 7.5{\%}.",
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Park, S, Sohn, HS, Cho, HH, Moon, HK, Han, YS & Ueda, O 2019, Effects of wakes on blade endwall heat transfer in high turbulence intensity. in Heat Transfer. Proceedings of the ASME Turbo Expo, vol. 5A-2019, American Society of Mechanical Engineers (ASME), ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition, GT 2019, Phoenix, United States, 19/6/17. https://doi.org/10.1115/GT2019-91493

Effects of wakes on blade endwall heat transfer in high turbulence intensity. / Park, Sehjin; Sohn, Ho Seong; Cho, Hyung Hee; Moon, Hee Koo; Han, Yang Seok; Ueda, Osamu.

Heat Transfer. American Society of Mechanical Engineers (ASME), 2019. (Proceedings of the ASME Turbo Expo; Vol. 5A-2019).

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

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Park S, Sohn HS, Cho HH, Moon HK, Han YS, Ueda O. Effects of wakes on blade endwall heat transfer in high turbulence intensity. In Heat Transfer. American Society of Mechanical Engineers (ASME). 2019. (Proceedings of the ASME Turbo Expo). https://doi.org/10.1115/GT2019-91493