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Non Symmetric Blade Root

IP.com Disclosure Number: IPCOM000033158D
Original Publication Date: 2004-Dec-25
Included in the Prior Art Database: 2004-Dec-25

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Abstract

The blades of turbines, compressors etc. have to be fixed at designated places in the machine. For this purpose the blade root can have a so called fire tree design. During operation, the blades have to stand high loads due to the centripetal force. Usually the highly loaded disc groove or blade root will restrict the component lifetime. In order to extend this lifetime, the blade root and the disc groove can have a non symmetric shape as it is shown schematically in Fig. 1. The eccentricity illustrated in this embodiment causes a relief in the maximum stress of a disc or blade, respectively. Due to this eccentricity, the critical points of closed-by grooves are not at the same height. The distance between two contiguous teeth is increased, which leads to a lower average stress in the cross section between the teeth. Furthermore, the difference in mass allocation between the pressure side and the suction side of the blade can be utilized to compensate specific loads of each blade.