Influence of Compound Angle on Adiabatic Film Cooling Effectiveness and Heat Transfer Coefficient for a Row of Shaped Film Cooling Holes

Abstract

The measurement of adiabatic film cooling effectiveness data and heat transfer coefficient data for a row of fanshaped film cooling holes at different compound angles is presented in this paper. The measurements are performed at engine-like temperature ratios in a hot gas test facility on a flat test plate. For the film cooling geometry, a row of five laidback-fanshaped holes was used. The temperature distribution on the flat plate is measured using infrared-thermography (IR). Steady state measurements are used to obtain the film cooling effectiveness. For the determination of the heat transfer coefficient ratio with and without film cooling on the test plate, a transient measurement technique is applied. Results for both the adiabatic film cooling effectiveness and the heat transfer coefficient ratio are given. The influence of different blowing ratios on the injection with compound angles of 0°, 30° and 45° will be discussed. From this study, the increasing compound angle showed only small effects on the pitch-wise lateral averaged adiabatic film cooling effectiveness but increased the heat transfer on the film cooled flat plate with coolant injection.

Effects of Swirl Velocities From Fan Assemblies Mounted on Lifting Surfaces

“…Regarding the external film cooling. Brauckmann and Wolfersdorf [13] and Aga et al [14] showed improvements on the thermal protection of the blade, using cooling holes with expanded exits (compound angle) aiming to reduce the momentum of the jel as well as to align the film-cooling traces on the blade. In addition, Hu and Ji [15] investigated, numerically, the eftect of blowing angle, illustrating that increased film-cooling effectiveness is achieved at higher blowing angles.…”

Analysis and Optimization of Double-Jet Film-Cooling Holes

“…To overcome the weakness of the cylindrical holes, the effects of shaped holes have been studied [3][4][5][6]. The shaped holes are designed to enhance the lateral spreading of the coolant because neighboring coolant jets immediately start merging downstream of the injection.…”

“…Baheri et al [5] numerically investigated the effect of the trench on the film-cooling effectiveness for the cylindrical and the shaped holes with and without the trench, and reported that the trench-shaped hole showed the best cooling performance. The experimental data of a shaped hole presented by Brauckmann and Wolfersdorf [6] represents the effects of the compound angle and blowing ratio on the heat transfer coefficient and the film-cooling effectiveness. They reported that the variation of the compound angles hardly affected the film-cooling effectiveness.…”

Effects of Compound Angle, Diffuser Angle, and Hole Pitch on Film-cooling Effectiveness

“…Brauckmann 과 Wolfersdorf (4) 는 측면 방향 분사각이 0, 30, 45°인 홴형상 홀에 대해 분사율이 0.5, 1, 1.5, 2 일 때의 막냉각 효율과 열전달계수에 대해 평가하였으 며, 측면 방향 분사각이 측면 방향 평균 막냉각 효 율에는 작은 영향만을 주었으나 막냉각 표면에서의 열전달은 증가되었다고 보고하였다. Nasir 등 (5) 는 측 면 방향 분사각이 0, 60° 인 원통형 막냉각 홀에 대 해 분사율을 0.5, 1.0, 1.5 로 변화시키며 연구를 수행 하였으며, 측면 방향 분사각이 막냉각 효율에 중요 한 변화를 주며 열전달계수를 높인다고 평가하였다.…”