Gas Turbine Synchronization Ring Thermal Mismatch

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Solution Overview

Problem

In gas turbine engines, the thermal mismatch between the compressor case and the synchronization ring in variable Stator Vane Angle (SVA) systems leads to inaccuracies in vane positional angles due to radial growth differences, caused by differing temperature responses to airflow, resulting in a radial gap that can deviate the vanes from intended angles.

Innovation Solution

The introduction of impingement openings in the engine case that direct flowpath gases to impinge on the synchronization ring, reducing thermal mismatch by increasing its thermal response and allowing for a reduced radial gap, thereby improving the accuracy of stator vane rotation and positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a radial gap is introduced between the compressor case and synchronization ring to accommodate thermal mismatch, then thermal expansion differences are accommodated, but vane angle accuracy deteriorates due to deviation from intended angles

Engineering Contradiction:

Improvethermal mismatch accommodationVSAvoidvane angle accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Hot gas path airflow is introduced as an intermediary thermal medium to transfer heat from the compressor case to the synchronization ring. The airflow passes through openings in the compressor case and directly impinges on the synchronization ring, serving as a thermal bridge that equalizes temperatures between the two components without requiring direct physical contact or eliminating the radial gap

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The temperature parameter of the synchronization ring is actively modified by exposing it to hot gas path airflow. This changes the thermal state of the synchronization ring to match the compressor case temperature, thereby reducing thermal mismatch. The system dynamically adjusts the thermal parameters of the synchronization ring to maintain temperature equilibrium with the compressor case throughout engine operation

Inventive Principle:

Principle #35Parameter changes

2Temperature

If the synchronization ring is positioned at the exterior of the engine case, then thermal access to case temperature is improved, but thermal response time deteriorates compared to the case

Engineering Contradiction:

Improvethermal access to case temperatureVSAvoidthermal response time

Core Design Contradiction:

TemperatureVSSpeed

Solution Approach 1:

Gas path airflow is utilized as a thermal transfer medium to accelerate heat transfer to the synchronization ring. The moving gas stream carries thermal energy from the compressor case interior to the exterior synchronization ring, significantly enhancing the thermal response rate compared to passive conduction through the case wall alone

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The gas path airflow serves as an intermediary that bridges the thermal connection between the compressor case and the externally positioned synchronization ring. This intermediary medium enables rapid thermal equilibration by directly contacting both the hot case interior surfaces and the synchronization ring, overcoming the thermal inertia of the externally positioned ring

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution enhances the accuracy of stator vane angle adjustments by minimizing thermal mismatch, leading to improved precision and reduced radial gaps, which is crucial for maintaining optimal engine performance throughout the engine cycle.

Implementation Method 1

The plurality of impingement openings are configured to direct flowpath gases from the interior of the engine case to impinge on the synchronization ring, thereby reducing a thermal mismatch between the engine case and the synchronization ring

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 2

Flowpath gases are directed through an opening exit of each impingement opening of the plurality of impingement openings to impinge on the synchronization ring, thereby reducing a thermal mismatch between the engine casing and the synchronization ring

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3760838B1Gas turbine variable vane system and method

Publication Date: 2022.12.28 RTX CORP

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AI summary

A stator vane angle system (62) includes an engine case (74), a plurality of stator vanes (64) located at an interior of the engine case. Each stator vane is rotatable about a stator vane axis (70). A synchronization ring (66) is located at an exterior (88) of the engine case. The synchronization ring is operably connected to each stator vane of the plurality of stator vanes such that movement of the synchronization ring urges rotation of each stator vane of the plurality of stator vanes about their respective stator vane axes. A plurality of impingement openings (82) extend through the engine case (74) from the interior (86) of the engine case to the exterior (88) of the engine case. The plurality of impingement openings are configured to direct flowpath gases from the interior of the engine case to impinge on the synchronization ring (66), thereby reducing a thermal mismatch between the engine case and the synchronization ring.