OVERALL COOLING EFFECTIVENESS ON A FLAT PLATE WITH BOTH FILM COOLING AND IMPINGEMENT COOLING IN HOT GAS CONDITION

This paper presents experimental results of temperature distribution on a flat plate with both film cooling and impingement cooling configurations. The film plate consists of 4 rows of round holes injected at an angle of 30. The impingement plate has a 6x6 jet array. Mainstream temperature is 100 degrees C, and coolant temperature is around 30 degrees C, which results in a density ratio of 1.2. To acquire a similar heat transfer condition with real engine, Bi number is matched by choosing MACOR as the plate material, which has a proper thermal conductivity of 1.7 W/m.K. A series of experiments were conducted, with blowing ratio ranges from 0.7 to 2.2. Infrared camera was used to measure the outer surface temperature. Overall cooling effectiveness was found to reach its maximum when blowing ratio is around 1.0. When the coolant continue to increase, the overall cooling effectiveness decreases and the cooling uniformity is also decreasing.