Gas Turbine Blade Shroud Seal Fin With Parallel Fluid Injection
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Solution Overview
Problem
Existing seal configurations in gas turbine engines fail to provide effective sealing between the tip end of blades and the outer casing, leading to significant leaks and inefficiencies.
Innovation Solution
A structure with a shroud and seal fin arrangement, featuring a cooling passage that injects sealing fluid parallel to the aft wall, reducing the discharge coefficient of leaking fluid and enhancing sealing effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If passive seal fins are used without injection, then the structure is simpler, but sealing capability is insufficient
Solution Approach 1:
The patent introduces active sealing by injecting sealing fluid through cooling passages located at the base of the seal fin. This pneumatic/hydraulic approach creates a pressurized sealing barrier that actively prevents leakage, transforming the passive seal fin structure into an active sealing system that reliably blocks fluid escape without increasing overall structural complexity
Solution Approach 2:
The patent changes the state of the sealing system from static (passive) to dynamic (active) by introducing fluid injection. The sealing capability is enhanced by controlling parameters such as injection pressure, flow rate, and timing, allowing the seal to adapt to varying operating conditions and maintain effective sealing under different thermal and pressure regimes
2Reliability
If sealing fluid is injected over the aft face of the seal fin, then sealing is attempted, but the sealing capability is much less effective
Solution Approach 1:
The cooling passages are positioned at the base of the seal fin to inject sealing fluid preemptively before the leaking flow can escape. This preliminary action creates a sealing barrier at the most critical location, preventing leakage at its source rather than attempting to block it downstream, thereby maximizing sealing efficiency and minimizing energy loss
Solution Approach 2:
Instead of injecting sealing fluid over the aft face (downstream) of the seal fin as in conventional approaches, the patent inverts the injection location to the base of the seal fin (upstream). This reversal allows the sealing fluid to counteract the leaking flow at its origin, creating a more effective sealing barrier that reduces energy loss and improves overall sealing performance
3Loss of substance
If lips are used to form a labyrinth-type dynamic seal joint, then leakage is limited, but complete sealing between tip end and block of abradable material is not guaranteed
Solution Approach 1:
The patent segments the sealing function into multiple components: the lip structure for initial leakage reduction, the cooling passages for fluid injection, and the seal fin base for creating a sealing barrier. This segmentation allows each component to perform its specific sealing function optimally, with the injected sealing fluid filling gaps and ensuring complete sealing where the labyrinth joint alone would be insufficient
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 structure achieves improved sealing by minimizing leaks, reducing heat generation, and maintaining flow uniformity, while being more tolerant to rubbing and simpler to cast.
Implementation Method 1
the cooling passage extends parallel to a surface of the aft wall closest to the cooling passage, so that a sealing fluid injected from the cooling conduct flows through the cooling passage and parallel to said surface of the aft wall
Data Source
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AI summary
The present invention provides a structure for a gas turbine engine. The structure comprises a body (2) extending from a root end to a tip end (2.1), a leading edge (LE) and a trailing edge (TE), wherein the leading edge is adapted to be faced towards a leaking flow (FL) and a shroud (3) arranged at the tip end of the body and comprising at least one seal fin (4) and a cooling conduct (5), the cooling conduct extending across the shroud. The seal fin comprises a fore wall (4.1) of smaller first height H1 and an aft wall (4.2) of a larger second height H2. A cooling passage (6) extends from the cooling conduct through the seal fin to communicate the cooling conduct with a leading first region (R1) of the shroud, extends parallel to a surface of the aft wall closest to the cooling passage. A sealing fluid (Fs) injected from the cooling conduct flows through the cooling passage and parallel to the surface of the aft wall. The present invention also provides a structure arrangement for a gas turbine engine and a gas turbine engine.