Turbine blade with internal cooling channels having variable cross section in flow direction, for local coolant flow control resulting in constant temperature profile

摘要

The cooling channels extend between blade foot and tip and contain esp. steam as coolant, and have a cross section, which varies in flow direction of the steam. They are formed as radial passages with circular cross section. Alternatively, the channels are formed by hollow spaces between radial grooves (50) in the inside of a wall (52) forming the blade (5), and have an insert (70) covering the grooves. The insert is a metal plate held pre-tensioned against rails (56) between two neighboring grooves.