Film-cooling

Patent Granted Film cooling (also called thin film cooling) is the most effective type of cooling,[20] and is a widely used type which works by pumping cool air out of the blade through small holes in the blade. This air creates a thin layer (the film) of cool air on the surface of the blade, protecting it from the 1300-1800 Kelvin high temperature air which can be hotter than the 1300-1400 Kelvin melting point of the blade.