Spring-Biased Seal Assembly with Heat Shield for Gas Turbine Leakage
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Solution Overview
Problem
Existing gas turbine seal assemblies face challenges in effectively reducing gas leakage around turbine blades due to the lack of efficient sealing mechanisms, particularly in high-temperature environments where materials are prone to stress and thermal gradients.
Innovation Solution
A seal assembly featuring a spring-biased seal arc segment with a segmented heat shield that provides axial biasing and thermal protection, utilizing ramped interfaces and a radially-extending leg to maintain contact and reduce gas flow, while a passage allows communication between cavities to enhance sealing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal arc segment is used to reduce gas flow around turbine blades, then gas leakage is reduced, but the spring maintaining contact is exposed to high temperatures causing thermal degradation
Solution Approach 1:
A heat shield is introduced as an intermediary component between the hot gas path and the spring. The heat shield includes a radially-extending leg positioned axially between the spring and seal arc segment, and an axially-extending leg radially inward of the spring, creating a thermal barrier that protects the spring from direct exposure to high-temperature gases while allowing the seal to maintain contact effectiveness
2Reliability
If the spring is positioned close to the seal arc segment to maintain contact, then sealing effectiveness is improved, but the spring is more exposed to hot gases causing thermal stress
Solution Approach 1:
The heat shield serves as a protective intermediary that allows the spring to remain in its effective position for maintaining seal contact while blocking direct thermal exposure. The shield's configuration with legs extending in multiple directions creates a physical barrier between the spring and the hot gas environment
3Temperature
If a heat shield is added to protect the spring from hot gases, then thermal protection is improved, but device complexity increases
Solution Approach 1:
The heat shield is divided into multiple legs (radially-extending leg and axially-extending leg) that can be integrated with the existing seal assembly structure. This segmented approach allows the heat shield to provide comprehensive thermal protection while being mounted on existing components, reducing the need for additional separate structures
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces gas leakage and maintains necessary internal stresses in the spring, even at elevated temperatures, by shielding the spring from hot gases and using pressurized fluid to prevent gas flow, thus enhancing the operational efficiency and durability of the gas turbine engine.
Implementation Method 1
A spring is configured to bias the seal arc segment axially relative to the seal arc segment toward the carriage
Implementation Method 2
A heat shield is radially inward of the spring. The heat shield includes a radially-extending, relative to the seal arc segment, leg axially, relative to the seal arc segment, between the spring and the seal arc segment
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A seal assembly includes a seal arc segment (66) defining first and second seal supports (70a, 70b) with a carriage (68) defining first and second support members (68a, 68b). The first support member supports the seal arc segment in a first ramped interface (72a), and the second support member supports the seal arc segment in a second ramped interface (72b). A spring (80) is configured to bias the seal arc segment axially. A heat shield (88) is radially inward of the spring.