Cooling at trailing edge of gas turbine airfoil is one of the most difficult problems because of its thin shape: high thermal load from both surfaces, hard-to-cool geometry of narrow passages, and at the same time demand for structural strength. In this study, heat transfer experiments by using transient technique were performed for cutback surfaces with three types of dimples (spherical, teardrop, and 45deg angled teardrop). The present results clearly showed the precise distribution of local film cooling effectiveness and Nusselt number. Although overall film cooling effectiveness was almost same among three dimpled surfaces, overall Nusselt number of teardrop and 45deg angled teardrop cases were larger than those of spherical dimple. As a result, film cooling performance of teardrop case was the highest of all.
