Rotor Blade Sealing Tabs for Secondary Air Leakage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Air leakage through interstitial spaces between rotor components in gas turbine engines limits the performance and durability of rotor discs, seals, and blades due to secondary air infiltration and leakage paths at the disc/blade interface.
Innovation Solution
A rotor assembly with sealing tabs on fixing members that project radially outward from the rotor disc, forming a face seal with the blade roots, which prevents secondary air from leaking out and enhances air retention, thereby reducing the negative impacts of hot combustion gases and improving sealing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If blades are mounted to rotor disc with fixing members, then blades are securely attached to rotor disc, but air leakage paths are formed at disc/blade interface allowing secondary air to escape
Solution Approach 1:
The fixing member is segmented into a body portion and a separate sealing tab portion. The sealing tab is positioned at the downstream end of the fixing member to specifically address air leakage at the disc/blade interface, while the body portion provides mechanical attachment strength. This segmentation allows each component to optimize its function independently.
Solution Approach 2:
The sealing tab acts as an intermediary element between the fixing member and the blade root interface. It provides a dedicated sealing surface that prevents air leakage paths without interfering with the mechanical attachment function of the fixing member body, thus mediating between structural requirements and sealing requirements.
2Temperature
If secondary air infiltrates interstitial spaces between rotor components, then cooling effect is provided to rotor discs and blades, but air leakage through disc/blade interface reduces cooling efficiency and increases temperature of rotor components
Solution Approach 1:
The sealing tab is positioned at the downstream end of the fixing member to preemptively block air leakage paths before secondary air can escape from the interstitial spaces. This preliminary sealing action maintains the cooling airflow within the rotor components, preventing energy loss and maintaining lower temperatures.
3Reliability
If sealing tab projects radially outward from fixing member, then air leakage is prevented at disc/blade interface, but device complexity increases
Solution Approach 1:
The sealing tab is merged with the fixing member body to form a single integrated component. This combining approach provides sealing functionality without requiring separate sealing devices or complex assembly procedures, thus minimizing device complexity while maintaining sealing effectiveness.
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 sealing tabs effectively minimize air leakage, retain secondary air, and reduce the temperature of rotor components, enhancing the durability and efficiency of gas turbine engines by creating a positive pressure differential that limits hot combustion gas infiltration.
Implementation Method 1
The sealing tab axially disposed at a downstream end of the radially outer tip of the fixing members proximate the rear face of the rotor disc creates a positive pressure differential that limits hot combustion gas infiltration and prevents secondary air leakage
Implementation Method 2
The presence of such colder secondary air may have a positive impact on the performance and/or durability of the rotor discs, seals and/or blades of rotors. However, secondary air ingested in such interstitial spaces may leak out therefrom through air leakage paths
Data Source
AI summary
The gas turbine engine rotor assembly includes a rotor disc with a plurality of sealing tabs projecting radially out from a peripheral surface of the rotor disc in the rear end portion thereof. A said sealing tab is disposed at a tip portion of a fixing member of the disc, formed between pairs of blade root slots, adjacent a trailing edge of the rotor disc. The sealing tabs help to reduce the leakage of secondary air out the back of a blade pocket defined between adjacent blades mounted on the rotor disc.