Wrapping fir type blade root for circumferentially installing blades

Abstract

The invention relates to a wrapping fir type blade root for circumferentially installing blades. A tooth-shaped surface is formed in the fir type blade root and a connecting end of a wheel edge; a blade root wrapping convex shoulder is formed in the upper end surface of the connecting end; a gap filling bar is arranged at the contact area between the bottom surface of the connecting end and the wheel edge; the fir type blade root is in contact with the wheel edge through the tooth-shaped surface; and the blade root wrapping convex shoulder is in contact connection with a convex shoulder of the wheel edge. According to the wrapping fir type blade root, a wrapping structure is integrated into the design of the fir type blade root, so that the outwards stretched axial displacement of the wheel edge is limited, the contact area between the blade and the wheel edge is enlarged, the stress level between the blade root and the wheel edge is greatly reduced and the safety and reliability of a steamship are improved; by virtue of the wrapping structure, the stress of the wheel edge can be better lowered than the stress of the blade root, the material strength performances of the blades and a blade wheel can be sufficiently exerted and the design requirement of the strength of the blade root can be easily met; and besides, by virtue of the structure form of the wrapping fir type blade root, the firmness degree of the connection between the blades and the blade wheel can be improved, so that the dynamic stress levels of the blades are reduced and the circumferential arrangement of the fir type blade root is further perfected.

Description

technical field [0001] The invention relates to a steam turbine moving blade, in particular to a blade root used for installing the steam turbine moving blade on an impeller or a rotating shaft. Background technique [0002] The blade is an important part of the turbomachinery, and the blade root is the connecting part that installs the blade on the impeller or the rotating shaft, and bears the huge centrifugal force and other loads of the blade. Improving the blade root structure can effectively reduce its stress level and improve the operational reliability of the blade. At present, the blade roots commonly used in steam turbines at home and abroad have structural forms such as T shape, outsourcing T shape, outsourcing double T shape, fork shape, fir tree shape and fungal shape. These types of blade roots mainly have the following characteristics. [0003] T-shaped blade root: simple structure, convenient processing and assembly, and reliable operation, but its bearing ca...

AI Technical Summary

Problems solved by technology

[0014] The problem to be solved by the present invention is: when the fir-tree-shaped blade root is used for the circumferential installation of the steam turbine blade, the axial displacement of the rim is relatively large, the contact area between the blade root and the rim is reduced, and the stress of the rim is relatively large, resulting in Due to the technical problem of reducing the safety and reliability of steam turbine blades, an outsourcing fir tree-shaped blade root for circumferential installation of blades is provided

Images