Segmented Near Flow Path Seal for Turbomachine Leakage
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Solution Overview
Problem
Turbomachines face challenges in preventing leakage of hot gases from the gas path into the wheelspace due to inadequate sealing between turbine stages, which can lead to reduced efficiency and increased wear on components.
Innovation Solution
The implementation of a near flow path seal member with a seal body and arm members that have varying thickness and dimensions, featuring specific surface profiles and recesses, to create a labyrinth seal that limits fluid exchange between the gas path and the wheel space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sealing methods are used between turbine stages, then the structure is simple, but gas leakage into the wheelspace increases
Solution Approach 1:
The seal member is divided into multiple arms (first arm member, second arm member, third arm member) extending from the seal body in different directions. Each arm independently contacts the rotor surface, creating multiple sealing points that collectively prevent gas leakage while maintaining structural integrity and adaptability to rotor position variations.
Solution Approach 2:
The seal member features varying arm lengths and thicknesses tailored to specific sealing locations. The first arm member has a first thickness and the second arm member has a second thickness, allowing each arm to be optimized for its specific sealing requirement. This local differentiation improves sealing effectiveness without requiring uniform complex structures throughout.
2Reliability
If the seal member has uniform thickness, then manufacturing is easier, but sealing performance against varying clearances deteriorates
Solution Approach 1:
The seal member incorporates varying thicknesses in different arms (first arm member with first thickness, second arm member with second thickness) to match the specific clearance requirements at different locations. This allows the seal to maintain optimal sealing performance across varying clearances while remaining manufacturable through standardized processes.
Solution Approach 2:
The seal member's geometric parameters (thickness, arm length, angle) are varied to optimize sealing performance. The first arm member and second arm member have different thickness parameters, and the arms are positioned at specific angles relative to the seal body, allowing the seal to adapt to varying clearance conditions without requiring complex manufacturing.
3Reliability
If the seal member uses complex geometry with varying dimensions, then sealing effectiveness improves, but manufacturing difficulty increases
Solution Approach 1:
The seal member is segmented into multiple arms with distinct functions, where each arm handles sealing at a specific location. This segmentation allows complex sealing effectiveness to be achieved through modular components that can be manufactured separately and assembled, reducing overall manufacturing difficulty.
Solution Approach 2:
Different portions of the seal member have different geometric properties (varying arm lengths, different arm thicknesses, specific angles) optimized for their local sealing requirements. This localized geometric variation improves sealing effectiveness while keeping each individual component relatively simple to manufacture.
Data Source
AI summary
A near flow path seal member for a turbomachine includes a seal body having a seal support member including a first end portion that extends to a second end portion through an intermediate portion. An arm member extends from the first end portion of the seal body. The arm member has a first end that extends to a second end to define an axial dimension of the arm member, a first edge that extends to a second, opposing edge to define a circumferential dimension of the arm member, and a surface having a profile that establishes a thickness variation of the arm member in each of the axial dimension and the circumferential dimension.