Axial-flow machine heat shield sealing strips
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Solution Overview
Problem
Existing axial-flow machines, such as gas turbines, face inefficiencies due to gaps between heat shield segments that allow cooling air to leak into the gas flow or hot gases to escape into the cooling air, compromising temperature protection for sensitive components.
Innovation Solution
The implementation of flat, strip-like sealing strips arranged in opposing grooves on the side faces of heat shield segments, secured by a key-type rotary sliding member, effectively seals gaps against air or gas flows radial or parallel to the rotor axis, preventing cooling air leakage and hot gas intrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat shield segments are used to protect temperature-sensitive components, then temperature protection is improved, but gaps between segments cause cooling air leakage and hot gas intrusion
Solution Approach 1:
The heat shield is divided into multiple segments that can be assembled around the rotor shaft, allowing for thermal expansion and manufacturing tolerances while maintaining effective temperature protection through the sealing strips at the joints
Solution Approach 2:
Flat strip-like sealing strips are introduced as intermediary elements between the heat shield segments. These sealing strips are arranged in opposing grooves on the side faces of adjacent segments, creating an effective seal that prevents cooling air leakage and hot gas intrusion while maintaining the segmented structure
2Reliability
If sealing strips are added to seal gaps between heat shield segments, then sealing effectiveness is improved, but device complexity increases
Solution Approach 1:
Flat strip-like sealing strips are used to seal the gaps between heat shield segments. These thin strip elements are arranged in opposing grooves on the side faces of adjacent segments, providing effective sealing without adding significant structural complexity
Solution Approach 2:
The sealing strips are arranged in grooves on the side faces of the heat shield segments, utilizing the radial dimension to create an effective seal. The strips extend axially along the gap and are positioned to seal both the radial and axial directions of potential leakage paths
3Reliability
If a locking device is used to secure sealing strips, then sealing reliability is improved, but ease of assembly deteriorates
Solution Approach 1:
Instead of securing the sealing strips directly, the locking device secures the heat shield segments themselves. The key-type rotary sliding member locks the segments axially to the rotor shaft, which indirectly secures the sealing strips in their grooves, simplifying the assembly process
Solution Approach 2:
The key-type rotary sliding member serves multiple functions: it locks the heat shield segments axially to the rotor shaft, secures the sealing strips in their grooves, and can be operated through the operating handle. This multi-functional element reduces the number of separate components needed
Data Source
Figure 1
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AI summary
The invention relates to an axial flow machine, in particular a gas turbine with axial hot gas flow. Gaps (7) between rotor- side heat shields (5) are blocked by mountable sealing strips (8',8' '), which are arranged with their longitudinal edges in opposing grooves in the side walls of the respective heat shields.