Gas Turbine Shroud Bleed Passage Tapering

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Solution Overview

Problem

Existing bleed passages in gas turbine engines lack enhanced flow efficiency, leading to suboptimal performance and potential issues like surge and backpressure.

Innovation Solution

The design incorporates a shroud with a bleed passage that features tapered sections and multiple orifices, including an inlet orifice and multiple outlet orifices, with passage legs that extend radially and circumferentially, optimizing airflow by reducing resistance and pressure differential.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional bleed passages are used, then the structure is simple, but the flow efficiency is insufficient

Engineering Contradiction:

Improvebleed air flow efficiencyVSAvoidpassage structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The bleed passage is divided into multiple separate passage legs (first passage leg, second passage leg, etc.) that extend from the inlet orifice to different outlet orifices. Each passage leg can be independently configured with its own taper angle and geometry, allowing optimization of airflow through each leg while maintaining overall system functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the passage legs have different geometric properties - specifically, the passage legs include tapered sections where the cross-sectional area changes along the flow direction. The taper angles can vary between different passage legs and different sections of the same leg, creating locally optimized flow conditions in different regions of the bleed passage system.

Inventive Principle:

Principle #3Local quality

2Productivity

If bleed passages with multiple outlet orifices are used, then the airflow distribution is improved, but the manufacturing complexity increases

Engineering Contradiction:

Improveairflow distribution efficiencyVSAvoidpassage fabrication difficulty

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The bleed passage system uses multiple discrete passage legs that can be manufactured as separate components or as distinct features within the shroud. This segmentation allows each passage leg to be optimized and manufactured independently, then integrated into the overall shroud structure with multiple outlet orifices positioned at different locations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The geometry of the passage legs, including taper angles, lengths, and cross-sectional areas, can be varied to optimize airflow distribution to multiple outlet orifices. By changing geometric parameters of each passage leg, the system achieves improved airflow distribution while maintaining manufacturability through standard aerodynamic design approaches.

Inventive Principle:

Principle #35Parameter changes

3Stress or pressure

If tapered passage sections are implemented, then the pressure differential is reduced, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvepressure differentialVSAvoidtaper angle accuracy

Core Design Contradiction:

Stress or pressureVSManufacturing precision

Solution Approach 1:

The passage legs incorporate tapered sections with specific taper angles that are optimized to reduce pressure differential and improve airflow. By carefully selecting and controlling the taper angle parameter, the design achieves reduced pressure losses while the taper geometry can be manufactured using standard machining or forming processes with conventional precision capabilities.

Inventive Principle:

Principle #35Parameter changes

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

This configuration enhances bleed air flow efficiency, balances air flowrate and pressure, and reduces vortices, thereby improving overall engine performance and preventing undesirable operational modes.

Implementation Method 1

At least a downstream section of the bleed passage circumferentially tapers as the downstream section of the bleed passage extends within the wall towards the outlet orifice

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

optimizing airflow by reducing resistance and pressure differential

Methodology Applied

Scientific EffectFlow resistance reduction: Pressure Drop

Data Source

PatentUS12152506B2Bleed passage arrangement for a gas turbine engine shroud

Publication Date: 2024.11.26 RTX CORP

AI summary

An apparatus is provided for a gas turbine engine. This engine apparatus includes a shroud, and the shroud includes a wall and a bleed passage. The wall includes an interior surface and an exterior surface. The wall extends circumferentially about an axis. The wall extends depthwise between the interior surface and the exterior surface. The interior surface forms a peripheral boundary of a flowpath that extends along the shroud. The bleed passage includes an inlet orifice and an outlet orifice. The bleed passage extends through the shroud between the inlet orifice and the outlet orifice. The inlet orifice is disposed in the interior surface and fluidly couples the flowpath to the bleed passage. At least a downstream section of the bleed passage circumferentially tapers as the downstream section of the bleed passage extends within the wall towards the outlet orifice.