Effect of Hole Space Ratio on Effusion Cooling Performance

Abstract

The film cooling effectiveness and local heat transfer coefficient for different hole space ratio have been experimentally investigated on a flat plate in the current study. The investigations were done by using a single test transient IR thermography technique. Three models of staggered holes arrangement are investigated. ). Each model is provided with five columns of holes, these models are arranged with staggered row holes. The holes diameter is 4mm, the longitudinal distance (X/D) is 10, and the span distance between two neighboring holes (S/D) are 3, 5, and 7 respectively. The attitude of the holes is fixed at inclination angle (θ= 30º ). The blowing ratios, cold to hot air flow ratio, have been changed three times (BR= 0.5, 1.0, and 1.5) during the experimental program. The experimental investigation showed that the thermal performance decreases as the space ratio (S/D) increases for all blowing ratios, and the film cooling effectiveness decreases as the blowing ratio increases for all the three models.