Angular Seal Element for Turbine Leakage Reduction
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Solution Overview
Problem
Turbine efficiency is compromised due to leakage of working fluid and coolant, caused by thermal expansion and high temperatures, which require additional coolant flow and purge air, limiting design and operation.
Innovation Solution
A seal element with angular features is positioned between static turbine components, connecting a pressurized cavity and the working fluid flowpath, directing coolant flow to seal interfaces and reduce leakage, while being thermally regulated by the coolant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If seals are located away from the flowpath to reduce thermal exposure, then seal thermal stress is reduced, but additional purge air is required to cool the inter-segment chute region
Solution Approach 1:
The seal element acts as an intermediary component that directly interfaces with the working fluid flowpath, eliminating the need for separate purge air systems. By positioning the seal at the interface between the pressurized cavity and flowpath, the design uses the seal structure itself to manage thermal exposure rather than requiring additional cooling air
Solution Approach 2:
The seal element incorporates angular features that segment the sealing surface, creating distinct zones for sealing engagement and fluid connection. This segmentation allows the seal to simultaneously maintain sealing integrity while managing thermal exposure through controlled fluid access
2Reliability
If seals are located closer to the gas path, then sealing effectiveness is improved, but active surface cooling is required to withstand thermal impact
Solution Approach 1:
The seal element performs self-cooling by utilizing the working fluid or pressurized cavity fluid that flows through its angular features. The seal's own structure facilitates heat dissipation through controlled fluid passage, eliminating the need for separate active cooling systems
Solution Approach 2:
The angular features create localized fluid channels at specific regions of the seal element, providing targeted cooling where thermal exposure is most intense. This local quality approach concentrates cooling effectiveness at the sealing interface without requiring system-wide active cooling
3Productivity
If clearances between components are reduced to improve turbine efficiency, then working fluid leakage is reduced, but thermal expansion requires larger clearances that cause leakage
Solution Approach 1:
The seal element provides dynamic adaptation to thermal expansion by maintaining sealing contact through its positioning between the pressurized cavity and flowpath. The seal compensates for clearance changes caused by thermal expansion, allowing the system to maintain small clearances for efficiency while the seal absorbs dimensional changes
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 seals interfaces, reduces coolant flow requirements, and enhances thermal management, improving turbine performance and efficiency by minimizing leakage and thermal stress on components.
Implementation Method 1
a first set of angular features disposed in the second surface, the first set of angular features fluidly connecting the pressurized cavity and the flowpath of the turbine
Implementation Method 2
the seal element including: a first surface shaped to be oriented radially outboard relative to a flowpath of the turbine, the first surface facing a pressurized cavity of the turbine
Data Source
AI summary
Systems and devices configured to seal interfaces/gaps between stationary components of turbines and manipulate a flow of coolant about portions of the turbine during turbine operation are disclosed. In one embodiment, a seal element includes: a first surface shaped to be oriented toward a pressurized cavity of the turbine; a second surface oriented substantially opposite the first surface and shaped to sealingly engage a contact surface of the static components; and a first set of angular features disposed in the second surface, the first set of angular features fluidly connecting the pressurized cavity and the flowpath of the turbine.