Gas Turbine Rim Seal With Radial Thickness Gradient
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In gas turbine engines, the rim seals between rotor blades and the rotor disc face challenges due to insufficient material in the blade platform area, leading to reduced retention capability and potential leakage, which affects performance and protection from hot gas path exposure.
Innovation Solution
A rotor assembly with a rim seal featuring a seal portion that increases in radial thickness from both ends to a midpoint peak, including foot portions that create a dead rim cavity for cooling airflow and prevent leakage, while matching the cross-sectional shape of the rim portion for effective sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rim seal is located radially in a cavity between rotor disc end and blade platform, then the rim seal can seal the gas path, but the scant material in platform area reduces bearing contact area and retention capability
Solution Approach 1:
The rim seal is divided into multiple functional segments: a seal portion for sealing, and multiple foot portions extending radially inwardly to engage with the rotor disc. This segmentation allows the seal to maintain sealing effectiveness while gaining additional retention points on the rotor disc surface, compensating for the scant material in the platform area.
Solution Approach 2:
The foot portions extend in a radial direction perpendicular to the primary sealing surface, creating a three-dimensional retention structure. This dimensional extension allows the rim seal to engage the rotor disc at multiple radial positions, increasing bearing contact area and retention capability without compromising the sealing function in the circumferential direction.
2Temperature
If cooling airflow is introduced to protect rotor disc from hot gas path, then rotor disc protection is improved, but hot gas path leakage may occur without proper sealing
Solution Approach 1:
The rim seal acts as an intermediary barrier between the hot gas path and the cooling airflow zone. The seal portion extends circumferentially to block the gas path, while the foot portions create a controlled interface for cooling airflow introduction. This intermediary structure enables cooling protection while maintaining gas path sealing integrity.
Solution Approach 2:
The rim seal provides localized sealing at the critical interface between the hot gas path and the rotor disc. By concentrating sealing functionality at the rim cavity location rather than throughout the entire gas path, the design enables targeted cooling airflow introduction in specific zones without compromising overall sealing reliability.
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 enhances the retention of the rim seal, reduces leakage, and allows for cooling airflow, thereby improving the operational performance and protection of the rotor disc from hot gas path exposure.
Implementation Method 1
A rim seal is installed across the abutment of the rotor blades to prevent hot gas path flow from leaking from the gas path between the rotor blades
Implementation Method 2
The first foot portion and the second foot portion provide a standoff defining a dead rim cavity between the rim seal and a low pressure rotor disc to allow cooling airflow to circulate in the dead rim cavity
Implementation Method 3
The seal portion has an increasing radial thickness with increasing distance from a first end of the rim seal and from a second end opposite the first end, to a seal peak located midway between the seal ends
Data Source
Figure 1
Figure 2~3
AI summary
A rim seal (70) for a rotor (48; 90) of a gas turbine engine (10) includes a seal portion (74) extending circumferentially across a rim cavity (68) of a rotor, the seal portion configured to seal the rim cavity and a first foot portion (76) extending radially inwardly from a first end (78) of the seal portion. A rotor assembly for a gas turbine engine includes a rotor disc (50; 94) and a plurality of rotor blades (52; 92) secured to the rotor disc defining a rim cavity between the rotor disc and a rim portion (66) of the plurality of rotor blades. A rim seal is located in the rim cavity and includes a seal portion extending circumferentially across the rim cavity, the seal portion configured to seal the rim cavity. The seal portion has an increasing radial thickness with increasing distance from a first end (78) of the rim seal and from a second end (78) opposite the first end.