Abstract: A method is provided including the steps: —first excitation of the object via a multifrequency signal; —detecting a first response signal of the object at one or multiple measuring points at the object; —transforming the first response signal from a time range into a frequency-dependent range; —selecting one or multiple frequencies, based on the frequency-dependent range; —second excitation of the object based on the selected frequencies; —detecting a second response signal of the object at one or multiple measuring points of the object; —ascertaining a mechanical parameter based on the second response signal.

Abstract: The removal of cooling air from the diffuser part of a radial stage of a compressor of a gas turbine is provided. The end stage of the compressor has a radial rotor disk (2) with a bladed diffuser (3). With the corresponding fastening elements (7) for the parts (20.1, 20.2) on the diffuser housing side, the diffuser blading (3) is used at the same time to connect the vane support (1) to the rear bearing housing (21). Compressed cooling air can be removed through either/both round holes (6.1) or/and slots (6.2), which are milled on the suction side of the diffuser vane (3). Through the removal openings (6.1, 6.2), the cooling air enters the blind holes (19) of the diffuser vane (3) and then further, through holes (19.1) in the diffuser housing outside (20.2), the cooling air discharge (10) arranged in the compressor housing.

Abstract: The removal of cooling air from the diffuser part of a radial end stage of a compressor of a gas turbine is provided. Compressed air is removed via a cooling air discharge (10) from a radial compressor stage, which comprises a rotor disk (2) and a bladed diffuser (20). The removal of cooling air may be brought about such that the cooling air is removed on one side through openings (6) on the housing side (20.1) of the diffuser (20) and is fed through cooling air channels (10) to the parts in contact with hot gas, including the outer wall of the bifurcated tube (17). The compressed air is guided to the diffuser outside (20.2) through cooling air holes (19) in the diffuser blade (3).