Improvement of Overall Film Cooling Performance by Optimizing Heat Transfer Enhancement on Dimpled Surface in Pulsating Channel Flow

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04321
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 19020:Thermal engineering-related
• Research Institution: Tokyo University of Agriculture and Technology
• Principal Investigator: MURATA Akira 東京農工大学, 工学(系)研究科(研究院), 教授 (60239522)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: フィルム冷却 / 脈動流 / 伝熱促進 / ガスタービン翼 / ディンプル / 非定常法 / 流れの可視化 / LES

Outline of Final Research Achievements

Cooling at trailing edge of gas turbine airfoil is one of the most difficult problems because of its thin shape: high thermal load from both surfaces, hard-to-cool geometry of narrow passages, and at the same time demand for structural strength are the reasons. In this study, to further improve the film cooling performance, optimization of surface geometry and pulsation parameters was performed for channel flow using URANS and LES. Then, the optimized conditions were applied to the film cooling. The numerical results were verified by experiments. Heat transfer coefficient and film cooling effectiveness were measured by a transient infrared thermography technique with consideration of three-dimensional heat conduction. The flow field was measured by a stereo PTV method. From the results, optimum values were identified and the principle of the enhanced convective cooling by the flow pulsation was explained.

Free Research Field

熱工学

Academic Significance and Societal Importance of the Research Achievements

高出力，高効率なガスタービンは航空機用，定置発電用に加え，その高速起動性・移動性により再生可能エネルギー系統安定化用・非常用電源としても高い関心を集めている．本研究は，高温化によるガスタービン熱効率向上の伝熱工学的制約（冷却困難部位）である翼後縁部のフィルム冷却を研究背景として，熱遮蔽性能維持下での熱伝達促進という新しい問題設定をする．そしてこれまでの成果を発展させ，混合層発達抑制とディンプル面熱伝達促進の最適化を同時実現することにより，さらなる性能向上とその原理説明を行い，エネルギー変換の高効率化とCO2削減に寄与する．