Gas Turbine Rotor Assembly Rim Seal Pressure Equalization
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Solution Overview
Problem
High axial loads on bolts/tie bars in compressor assemblies of gas turbine engines require numerous high-strength connectors, increasing weight and cost due to the need for both structural integrity and gas path sealing.
Innovation Solution
A rotor assembly design with a rim seal and pressure equalization path between rotor stages, reducing the axial load on connectors by matching the pressure in the rim cavity to the main cavity, allowing connectors to focus solely on structural connection rather than sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If numerous high-strength bolts/tie bars are used to maintain structural integrity and seal the gas path, then the structural strength and sealing reliability are improved, but the weight and cost of the compressor increase
Solution Approach 1:
The invention divides the drum cavity into two separate pressure zones: a rim cavity portion at gas path pressure and a main cavity portion at lower pressure. This segmentation allows different sealing strategies for different regions, reducing the overall sealing load on connectors while maintaining structural integrity.
Solution Approach 2:
A rim seal is introduced as an intermediary component between the first and second rotor stages at the rim cavity portion. This rim seal specifically handles the sealing function at the high-pressure gas path interface, allowing the bolts/tie bars to focus on structural connection rather than dual structural-sealing function, thereby reducing their required strength and number.
2Reliability
If numerous high-strength bolts/tie bars are used to maintain structural integrity and seal the gas path, then the structural strength and sealing reliability are improved, but the cost of the compressor increases
Solution Approach 1:
The invention divides the drum cavity into two separate pressure zones: a rim cavity portion at gas path pressure and a main cavity portion at lower pressure. This segmentation allows different sealing strategies for different regions, reducing the overall sealing load on connectors while maintaining structural integrity.
Solution Approach 2:
A rim seal is introduced as an intermediary component between the first and second rotor stages at the rim cavity portion. This rim seal specifically handles the sealing function at the high-pressure gas path interface, allowing the bolts/tie bars to focus on structural connection rather than dual structural-sealing function, thereby reducing their required strength and number.
3Reliability
If the rim cavity portion is at gas path pressure, then the connectors must handle both structural loads and sealing loads, but this increases the axial load on connectors and reduces their service life
Solution Approach 1:
The invention divides the drum cavity into two separate pressure zones: a rim cavity portion at gas path pressure and a main cavity portion at lower pressure. This segmentation allows different sealing strategies for different regions, reducing the overall sealing load on connectors while maintaining structural integrity.
Solution Approach 2:
A rim seal is introduced as an intermediary component between the first and second rotor stages at the rim cavity portion. This rim seal specifically handles the sealing function at the high-pressure gas path interface, allowing the bolts/tie bars to focus on structural connection rather than dual structural-sealing function, thereby reducing their required strength and number.
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
This design extends the life of connectors, reduces weight and cost by allowing for fewer and lower-strength connectors, while maintaining structural integrity and sealing effectiveness.
Implementation Method 1
A rotor assembly design with a rim seal and pressure equalization path between rotor stages, reducing the axial load on connectors by matching the pressure in the rim cavity to the main cavity
Data Source
AI summary
The present disclosure relates to a rotor assembly for a gas turbine engine, the rotor assembly comprising a first rotor stage having a first disc portion with a peripheral first rim portion and a second rotor stage, the second rotor stage having a second disc portion with a peripheral second rim portion. The second rotor stage is axially adjacent and downstream of the first rotor stage and the second rim portion has an axial extension extending towards the first rim portion such that the axial extension of the second rim portion defines a rotor drum cavity between the first and second disc portions. The second rotor stage further comprises a drive arm extending within the drum cavity to the first disc portion, the drive arm being connected to the first disc portion by at least one connector. The drive arm divides the drum cavity into radially outer rim cavity portion and a radially inner main cavity portion. The rotor assembly further comprises a rim seal located between the axial extension of the second rim portion and the first rim portion, and a pressure equalisation path extending from the rim cavity portion to the main cavity portion.