Bleed Valve Shims for Gas Turbine Leakage and Flow Control

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Solution Overview

Problem

Existing bleed valve assemblies in gas turbine engines suffer from air leakage between the piston and the manifold when closed, and the fixed flow rate of bleed air when opened, due to tolerances and unevenness at their interface.

Innovation Solution

A bleed valve assembly with a manifold, valve housing, and piston, where shims are used to adjust the axial distance between the piston and the manifold, allowing for varying flow rates and minimizing leakage by engaging the valve seal between the piston and the manifold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a piston is used to close the air passageway in a bleed valve assembly, then the valve can block bleed air flow, but air leakage occurs between the piston and manifold due to tolerances and unevenness

Engineering Contradiction:

Improvesealing performanceVSAvoidair leakage

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A valve seal acts as an intermediary element between the piston and manifold to prevent air leakage. The seal is compressed between these two components to create a reliable barrier that blocks harmful air leakage while maintaining the sealing function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The valve seal utilizes a flexible thin film structure that can deform to accommodate tolerances and unevenness between the piston and manifold surfaces. This flexibility allows the seal to maintain contact and prevent leakage despite manufacturing variations.

Inventive Principle:

Principle #30Flexible shells and thin films

2Adaptability or versatility

If the gap between piston and manifold is fixed by manufacturing tolerances, then the structure is simple, but the bleed air flow rate cannot be adjusted

Engineering Contradiction:

Improveflow rate adjustabilityVSAvoidvalve assembly structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system transitions from a fixed gap structure to a dynamic adjustable structure. The piston can be positioned at different distances from the manifold surface, allowing the bleed air flow rate to be varied. This dynamic adjustment capability enables adaptability while maintaining a relatively simple overall structure.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12264685B1Bleed valve assembly with valve shims for varying bleed flow in gas turbine engine compressors and method for operating

Publication Date: 2025.04.01 ROLLS ROYCE CORP

AI summary

A bleed valve assembly includes a manifold coupled to a case of a compressor of a gas turbine engine to control a flow of bleed air exiting the compressor, a valve housing coupled with the manifold, a piston configured to move selectively relative to the valve housing and the manifold, and one or more shims located between the valve housing and the piston.