Alternating Gap Flow Inhibitor for Turbomachine Shroud
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Solution Overview
Problem
Turbomachinery faces damage from hot gas ingestion due to circumferential pressure gradients, which existing methods like secondary cooling air injection negatively impact engine performance.
Innovation Solution
The implementation of alternating restrictive and unrestrictive gaps between the inner and outer shrouds, utilizing labyrinth pockets to create pressure loss mechanisms and reduce hot gas flow, while maintaining engine performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If secondary cooling air is injected from the inner shroud into the gap between turbine nozzles and inner shroud, then the outer shroud is protected from hot gas damage, but the turbomachine performance decreases
Solution Approach 1:
The patent introduces flow inhibitors as intermediary structures positioned in the gap between the inner and outer shrouds. These flow inhibitors act as mediators that block hot gas ingestion paths without requiring secondary cooling air injection, thus protecting the outer shroud while avoiding the performance penalty associated with cooling air injection
Solution Approach 2:
The patent extracts the harmful hot gas flow from the system by introducing flow inhibitors that remove the hot gas ingestion path. The flow inhibitors are separate components that take out the problematic hot gas flow without affecting the main cooling system, allowing protection of the outer shroud without sacrificing turbomachine performance
2Ease of manufacture
If the gap between inner shroud and support structure is kept open, then manufacturing and assembly are simplified, but hot gas flows into the gap and damages the outer shroud
Solution Approach 1:
The flow inhibitors serve as intermediary elements that are introduced into the gap between the inner shroud and support structure. These inhibitors block the hot gas flow path while allowing the gap itself to remain open for manufacturing and assembly simplicity, thus resolving the contradiction between ease of manufacture and protection from hot gas damage
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
Effectively prevents hot gas ingestion into the outer shroud, reducing damage and maintaining turbomachine performance by inducing pressure losses and enhancing convective heat transfer.
Implementation Method 1
The at least one gap alternates between at least one restrictive gap and at least one unrestrictive gap and is capable of creating at least one pressure loss mechanism to reduce a hot gas flow in the at least one gap
Implementation Method 2
enhancing convective heat transfer
Data Source
AI summary
Disclosed is a shroud for a turbomachine including at least one support structure and at least one inner shroud disposed at a gas path of a turbomachine. The at least one inner shroud and the at least one support structure have at least one gap therebetween. The at least one gap alternates between at least one restrictive gap and at least one unrestrictive gap and is capable of creating at least one pressure loss mechanism to reduce a hot gas flow in the at least one gap. Further disclosed is a turbomachine and a method for reducing ingestion of hot gas in a turbomachine.