Variable Outer Air Seal Support for Turbomachine Flowpath Obstruction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Supporting blade outer air seal (BOAS) assemblies in turbomachines is challenging due to fasteners protruding into flowpaths and difficulty in accommodating direct clamping loads, which complicates fastener design.
Innovation Solution
A variable outer air seal support system featuring a groove for a connector pin with an undulating design and a connector pin having a threaded bore and extension, allowing for axial movement and pivoting, which enables secure attachment and movement of BOAS segments without obstructing airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fasteners are used to support BOAS assemblies, then secure attachment is achieved, but fasteners protrude into flowpaths causing obstruction
Solution Approach 1:
The fastener head is extracted from the traditional protruding position and recessed into a groove in the case, removing the harmful protrusion into the flowpath while maintaining the attachment function through the connector pin extending through the slot
Solution Approach 2:
The connector pin head is nested within the groove of the case, with the pin itself extending through the slot to provide attachment. This nesting arrangement allows the fastening function to be maintained while the head is concealed within the case structure, eliminating flowpath obstruction
2Reliability
If direct clamping loads are applied to BOAS assembly components, then secure support is achieved, but components cannot accommodate the loads making fastener design difficult
Solution Approach 1:
The support system is segmented into distinct functional elements: the groove structure for load distribution, the slot for controlled movement, and the connector pin for attachment. This segmentation allows each component to handle specific aspects of the clamping load, simplifying the overall fastener design while maintaining support security
Solution Approach 2:
The connector pin acts as an intermediary element between the case and the BOAS segment. It transfers clamping loads through the slot without requiring the BOAS segment components to directly accommodate high clamping forces, thereby simplifying the fastener design while maintaining secure support
3Productivity
If BOAS segments are made adjustable for clearance control, then operational efficiency is enhanced, but mechanism complexity increases
Solution Approach 1:
The slot is designed to allow dynamic adjustment of the BOAS segment position along its length. This enables clearance control during operation while maintaining a relatively simple mechanism that relies on the geometric constraints of the slot rather than complex actuation systems
Solution Approach 2:
The system allows for parameter changes in the clearance between the blade tip and the BOAS by adjusting the segment position within the slot. This enables operational efficiency enhancement through parameter adjustment while keeping the mechanism simple, as the adjustment is achieved through the predefined slot geometry rather than complex control systems
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A variable outer air seal support system according to an exemplary aspect of the present disclosure includes, among other things, a case having a plurality of slots, and an extension of a variable outer air seal segment. The extension provides at least one extension aperture. A connector pin is configured to move within the slot to move the variable outer air seal segment from a first position to a second position. The variable outer air seal segment overlaps a circumferentially adjacent variable outer air seal segment more in the first position than in the second position.