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%.
|Title of host publication||Heat Transfer|
|Publisher||American Society of Mechanical Engineers (ASME)|
|Publication status||Published - 2019|
|Event||ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition, GT 2019 - Phoenix, United States|
Duration: 2019 Jun 17 → 2019 Jun 21
|Name||Proceedings of the ASME Turbo Expo|
|Conference||ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition, GT 2019|
|Period||19/6/17 → 19/6/21|
Bibliographical noteFunding Information:
The authors wish to acknowledge support for this study by Korea Southern Power Co., Ltd. and Mitsubishi Hitachi Power Systems, Ltd. This work was supported by the Human Resources Development program (No.20174030201720) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), grant funded by the Korea government Ministry of Trade.
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