Film cooling effectiveness and heat transfer were measured in squealer tip configurations on the blade tip surface. Three different shelf squealer tip geometries were studied: conventional, vertical, and inclined. The experiment was carried out in a wind tunnel with an inlet mainstream Reynolds number, based on the axial chord length of the blade, of 140,000. The experiments were conducted in five blades in linear cascade with an averaged turbulence intensity of 8.5%. The film cooling effectiveness and heat transfer coefficient on the tip surface were obtained using the transient IR thermography technique. For the pressure side film cooling holes, averaging blowing ratios (M) of 1.0 and 2.0 were set. The results showed the film cooling effectiveness distributions on the tip surface. Owing to the mainstream, the cooling effect appeared after x/Cx = 0.15 and the film cooling effectiveness tended to increase toward downstream of the trailing edge. Additionally, the heat transfer distributions were investigated regarding the film cooling holes. In the presence of film cooling holes, the heat transfer distribution had more uniformity than without them on the pressure side. As the blowing ratio increased from 1 to 2, the heat transfer was decreased on the tip surface. The heat transfer ratio represented the change of heat transfer distribution with and without film cooling holes. Those of results were compared in three squealer tip geometries. The overall area-Averaged net heat flux reduction (NHFR) levels on the tip surface were enhanced as the blowing ratio increased. The NHFR of the shelf squealer tip configurations was better than that with the conventional squealer tip.
|Title of host publication||Heat Transfer|
|Publisher||American Society of Mechanical Engineers (ASME)|
|Publication status||Published - 2018|
|Event||ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition, GT 2018 - Oslo, Norway|
Duration: 2018 Jun 11 → 2018 Jun 15
|Name||Proceedings of the ASME Turbo Expo|
|Other||ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition, GT 2018|
|Period||18/6/11 → 18/6/15|
Bibliographical noteFunding Information:
This work was supported by the Human Resources Development program (No.20174030201720) and the Energy Technology Development program (No.20161120100370) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Trade, Industry and Energy.
Copyright © 2018 ASME.
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