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막 냉각 홀의 복합각도에 따른 유동 특성 및 냉각 효율 변화에 관한 실험적 연구
최제문(Jaemun Choi),박희성(Heesung Park) 대한기계학회 2022 大韓機械學會論文集B Vol.46 No.4
막 냉각 기술에 사용되는 원통형 홀의 유동 특성과 냉각 효율을 비교 분석하기 위한 실험적 연구를 수행하였다. 유동 레이저 가시화 및 열화상 기술을 사용해 저속 풍동에서 복합각도에 대해 0.3~2까지의 분사비로 유동 및 열특성을 측정하였다. 중심선과 스팬 방향에 대한 냉각 효율은 복합각도 0°에서 분사비가 0.3일 때 가장 높았다. 반면 면적에 대한 평균 냉각 효율은 오히려 복합각도 90°와 180°의 모든 분사비에서 0°에 비해 높았다. 분사비가 2일 때 복합각도 90°와 180°의 경우 0°보다 면적 평균 막 냉각효율이 171% 향상되었다. 결과적으로 원통형 형상의 유동 가시화 특성과 그에 따른 냉각 효율 분석을 통해 복합각도의 변화가 막 냉각 효율에 영향을 미치는 것을 알 수 있다. An experimental investigation is conducted to analyze the flow characteristics and cooling effectiveness of cylindrical holes used in film cooling technology. Five blowing ratios from 0.3 to 2 are selected in this study using flow laser visualization and thermal imaging techniques. The cooling effectiveness at the centerline and span direction is the highest when the blowing ratio is 0.3 at a compound angle of 0°. However, the average cooling effectiveness for the area is improved with the compound angles of 90° and 180°. When the blowing ratio is 2, the area average film cooling effectiveness is 171% higher compared to 0° in the case of the compound angles of 90° and 180°. As a result, it can be noted that the change in the compound angle affects the film cooling effectiveness owing to different horseshoe vortices and film flow dispersion.
차세대 초고온 가스터빈의 가변 충돌 및 이중벽냉각 구조 최적화 기술과 3D printer/정밀 가공의 융합 제조 기술 개발
권화빈(Hwabhin Kwon),최제문(Jaemun Choi),김준섭(Joon Seob Kim),정예림(Ye Lim Jung),박희성(Heesung Park) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.05
A complex cooling structure is applied to protect the high-temperature components of the next-generation gas turbine, and a single crystal precision casting method is applied to manufacture it. The single crystal casting method has the disadvantage that the process is complicated and the manufacturing time is long. To compensate for this, a study was conducted to apply a 3D printer and precision processing technology in combination. The double-wall cooling structure applied to the single-stage vane was optimized through numerical simulation studies, and this was verified through experiments. The effusion angles of film cooling and impingement cooling applied to the double wall cooling structure are designed to be 35 ˚ and 90 ˚, respectively. A wind tunnel test was performed to experimentally determine the film cooling performance. In order to increase the film cooling performance, the structure of the delta wing tip and delta wing flop is applied. Heat transfer characteristics and cooling performance are analyzed using a thermal imaging camera and flow visualization technology. Through the development of a process the combines 3D printer and precision processing, the single-stage vane derived by this study is produced. By applying a process that combines 3D printer and precision machining, a single-stage vane derived by this study is manufactured and is evaluated.