Compressor Exit Seal with Sacrificial Piece and Cooling
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Solution Overview
Problem
Gas turbine engine compressor sections face challenges in managing high temperature-induced stresses on the rotor hub and maintaining effective sealing between the rotor hub and compressor exit guide vane, which affects pressure and temperature increases and leakage control.
Innovation Solution
A non-contact seal arrangement is implemented, featuring a sacrificial piece mounted on the housing with radially outward shoes and air feed holes in the compressor exit guide vane, allowing controlled leakage to cool the hub and minimize thermal exposure, while being self-adjusting to maintain low leakage rates and thrust balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pressure and temperature of air leaving the compressor are increased, then the compressor performance is improved, but the thermal stresses on the rotor hub increase
Solution Approach 1:
A sacrificial piece is introduced as an intermediary component between the rotor hub and the non-contact seal. This sacrificial piece absorbs the thermal stresses and wear, protecting the rotor hub while allowing the compressor to operate at higher pressures and temperatures for improved performance
Solution Approach 2:
The sacrificial piece is designed as a consumable component that can be easily replaced. By using a disposable sacrificial piece rather than protecting the expensive rotor hub directly, the system enables higher operating temperatures and pressures while managing thermal stress through periodic replacement of the sacrificial component
2Reliability
If a seal arrangement is placed between the rotor hub and compressor exit guide vane, then leakage control is improved, but the complexity of the device increases
Solution Approach 1:
The non-contact seal uses aerodynamic forces and spring biasing to automatically maintain the seal shoes in contact with the sacrificial piece, creating a self-regulating sealing system that adapts to thermal expansion and wear without external control mechanisms
Solution Approach 2:
The seal arrangement employs dynamic elements including spring-biased seal shoes that can move radially to maintain contact with the sacrificial piece, and air feed holes that provide dynamic cooling and lubrication, allowing the seal to adapt to changing operating conditions while maintaining low leakage
3Temperature
If cooling air is fed through the compressor exit guide vane, then the rotor hub thermal exposure is reduced, but the air feed system complexity increases
Solution Approach 1:
The compressor exit guide vane serves multiple functions: it guides the airflow for compression, provides structural support, and acts as the feed path for cooling air to the rotor hub. This multi-functionality eliminates the need for separate cooling air delivery systems, reducing overall complexity while effectively cooling the rotor hub
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 thermal stresses on the rotor hub, enhances sealing efficiency, and minimizes leakage, thereby improving the compressor's performance and operational reliability.
Implementation Method 1
A non-contact seal arrangement is implemented, featuring a sacrificial piece mounted on the housing with radially outward shoes and air feed holes in the compressor exit guide vane, allowing controlled leakage to cool the hub
Implementation Method 2
the tapped air also passes through a controlled leakage path between the non-contact seal and the sacrificial piece to pass into a chamber downstream and towards a turbine section
Data Source
Figure 1
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Figure 4~5
AI summary
A gas turbine engine compressor section (100) has a hub (110) carrying a last row of compressor blades (106). A compressor exit guide vane (108) is downstream of the last row of compressor blades (106). A housing (109) is radially inward of the compressor exit guide vane (108). A non-contact seal (116) is positioned on one of the housing (109) and the hub (110).