1. Internal cooling for turbine blades

Since the 1960s, cooling techniques have evolved considerably (figure 1 ). Initially, blades were cooled using radial pipes. In the 1970s, multiple-feed systems with film cooling were developed. For today's gas turbines, external heat transfer techniques using film cooling and internal convection have been significantly improved: multi-pass channels with turbulence promoters, fine needle-like fins (or fine pine, as the English term will be used in the rest of this text), impact jet cooling.