Blade for gas turbines with choke cross section at the trailing edge

A gas-turbine guide element for directing the flow of hot air, said gas turbine guide element comprising:

• a trailing edge region at which air flow separates from the guide element, said trailing edge region including at least two walls arranged approximately parallel to each other and connected to each other by a plurality of ribs;
• internal cooling passages being defined between said ribs, said internal cooling passages being adapted for carrying cooling medium for cooling said guide element through the cooling passages and discharging the cooling medium from the guide element at the trailing edge region essentially parallel to and between said walls;
• at least some of said ribs being arranged so as to terminate approximately flush with a trailing edge of the trailing edge region;
• said ribs arranged to terminate approximately flush with the trailing edge are choke ribs and a rate of flow of cooling medium through the guide element is a function of the dimensioning of the internal cooling passages defined between the choke ribs;
• and
• the choke ribs each have a width (e) parallel to the trailing edge and are arranged at a distance apart from center-to-center by a rib spacing (f), such that the ratio of width (e) to rib spacing (f) is within a range of approximately 0.35 to 0.75.