Abstract: A turboshaft gas turbine engine comprises, in fluid flow series, a gas-generator compressor, a combustor, a gas-generator turbine, and a free power turbine. The expansion ratios of the turbines are dependent upon an outlet temperature of the combustor, and an expansion relationship between the turbines is defined as the ratio of expansion ratios of the turbines over a running range of non-dimensional power outputs of the gas turbine engine. A second derivative of the expansion relationship is from 0.6 to 1.0.

Abstract: The present invention relates to a cooled turbine blade for a gas-turbine engine having at least one cooling duct (14) extending radially, relative to a rotary axis of the gas-turbine engine, inside the airfoil and air-supply ducts (12) issuing into said cooling duct, characterized in that the cooling duct (14) extends into the blade root (6) in order to generate close to the wall a cooling airflow moved at high circumferential velocity and radially in helical form and that in the area of the blade root (6) at least one nozzle-shaped air-supply duct (12) issues into the cooling duct (14) tangentially or with a tangential velocity component.

Abstract: In impingement air cooling of gas turbine components, cooling air velocity packs of a certain amplitude and a given frequency are applied to impingement air openings, with intervallic annular swirl structures being formed which penetrate a cross-flow and hit a component to be cooled with high intensity, thus providing for efficient cooling. In order to obtain annular swirl structures with optimum cooling effect, the Strouhal number, which is determined by a ratio of amplitude, frequency of the velocity packs and size of impingement air cooling openings, ranges between 0.2 and 2.0, and preferably between 0.8 and 1.2.

Abstract: Passive shroud cooling of rotor blades (5) is accomplished by a multitude of cooling-air flows introduced into the hot-gas flow upstream of the rotor blades on the outer circumference, these cooling-air flows, depending on the aerodynamic and geometrical conditions, being orientated at a defined radial angle and a circumferentially related tangential angle such that the cooling air primarily and essentially hits the thermally highly loaded bottom surface (11) of the outer shrouds (6) allover. In the apparatus for the performance of the method, cooling air passages (9) tangentially and radially orientated to the hot-gas flow are provided in an area of a casing section (3) which protrudes beyond the stator blades (1) in the downstream direction, this casing section (3) interrupting the transport of cooling air in the axial direction.

Abstract: In impingement air cooling of gas turbine components, cooling air velocity packs of a certain amplitude and a given frequency are applied to impingement air openings, with intervallic annular swirl structures being formed which penetrate a cross-flow and hit a component to be cooled with high intensity, thus providing for efficient cooling. In order to obtain annular swirl structures with optimum cooling effect, the Strouhal number, which is determined by a ratio of amplitude, frequency of the velocity packs and size of impingement air cooling openings, ranges between 0.2 and 2.0, and preferably between 0.8 and 1.2.

Abstract: Passive shroud cooling of rotor blades (5) is accomplished by a multitude of cooling-air flows introduced into the hot-gas flow upstream of the rotor blades on the outer circumference, these cooling-air flows, depending on the aerodynamic and geometrical conditions, being orientated at a defined radial angle and a circumferentially related tangential angle such that the cooling air primarily and essentially hits the thermally highly loaded bottom surface (11) of the outer shrouds (6) allover. In the apparatus for the performance of the method, cooling air passages (9) tangentially and radially orientated to the hot-gas flow are provided in an area of a casing section (3) which protrudes beyond the stator blades (1) in the downstream direction, this casing section (3) interrupting the transport of cooling air in the axial direction.