| Title |
Measurement of Film Cooling Effectiveness and Heat Transfer of Rectangular-Shaped Film Cooling Holes |
| Keywords |
Film cooling ; 막냉각 ; Rectangular-shaped hole ; 사각홀 ; Heat transfer ; 열전달 ; TLC technique ; 감온성 열액정법 |
| Abstract |
An experimental study has been conducted to measure the local film-cooling effectiveness and the heat transfer coefficient for a single row of rectangular-shaped holes. Four different cooling hole shapes such as a straight rectangular hole, a rectangular hole with laterally expanded exit, a circular hole and a two-dimensional slot are tested. A technique using thermochromic liquid crystals is applied to determine adiabatic film cooling effectiveness values and heat transfer coefficients on the test surface. Both film cooling effectiveness and heat transfer coefficient are measured for various blowing rates and compared with the results of the cylindrical holes and the two-dimensional slot. The flow patterns downstream of holes are calculated numerically using a commercial package. The results show that the rectangular holes provide better performance than the cylindrical holes. For the rectangular holes with expanded exit, the penetration of jet is reduced significantly, and the higher and more uniform cooling performance is obtained even at relatively high blowing rates. |