Turbomachinery Inner Ring System Thermal Deformation Control

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Solution Overview

Problem

Turbomachines face efficiency reductions due to thermal deformations of inner ring segments, leading to increased sealing gaps and leaks, which are exacerbated by the 'cording effect' during operation, resulting in higher wear and reduced efficiency.

Innovation Solution

An inner ring system where the inner ring is immovably fixed to the guide vane's journal, utilizing a plate-shaped fastening element and a seal carrier with axially acting spring force, supported by a bushing and seal carrier, to maintain constant distance from the turbomachine housing, minimizing thermal deformations and leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the inner ring is designed as a segmented structure to facilitate assembly and maintenance, then the ease of manufacture and maintenance is improved, but thermal deformations cause cording effects that increase sealing gaps and leakage

Engineering Contradiction:
Improveease of assemblyVSAvoidsealing performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The inner ring is divided into multiple segments that can be assembled separately and connected through connection elements. This segmentation allows for easier assembly and maintenance while the connection elements are designed to maintain structural integrity and minimize thermal deformation effects on sealing performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection elements between ring segments are designed with specific geometric parameters and material properties that compensate for thermal expansion. By carefully selecting and optimizing these parameters, the structure accommodates thermal deformations while maintaining adequate sealing gaps and preventing excessive leakage.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the inner ring segments are allowed to move relative to each other during operation to accommodate thermal expansion, then the stability under thermal load is improved, but sealing gaps increase and leakage worsens

Engineering Contradiction:
Improvethermal stabilityVSAvoidleakage
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The connection elements between ring segments are designed to allow controlled relative movement that accommodates thermal expansion. This dynamic design enables the structure to adapt to temperature changes while maintaining optimal sealing gaps, preventing excessive leakage that would occur with rigid fixed connections.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Connection elements serve as intermediaries between adjacent ring segments, mediating the thermal expansion effects. These intermediaries allow controlled movement and stress distribution, enabling the segments to expand thermally while maintaining proper sealing clearances and minimizing leakage paths.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the inner ring is rigidly fixed to prevent any movement, then the sealing gaps are maintained consistently, but thermal deformations cause increased stress and potential damage

Engineering Contradiction:
Improvesealing performanceVSAvoidstructural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

Different regions of the inner ring structure have different degrees of rigidity. The sealing regions are designed with rigid connections to maintain consistent sealing gaps, while the connection elements between segments have controlled flexibility to accommodate thermal expansion. This local differentiation of structural properties allows the structure to maintain sealing performance while managing thermal stresses.

Inventive Principle:
Principle #3Local quality

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 maintains consistent sealing gaps, reduces leakage, and enhances turbomachine efficiency by preventing undesirable thermal deformations and wear, while allowing for easy maintenance and production using additive manufacturing.

Implementation Method 1

the inner ring system comprises at least one seal carrier arranged at least partially radially on the inside of the inner ring, by means of which an axially acting spring force is exerted on the inner ring

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

the inner ring being supported radially inward on the bushing

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3170987B1Internal ring system for turbomachinery
Publication Date: 2020.02.19 MTU AERO ENGINES GMBH
  • EP3170987B1 patent drawingFigure 1~2
  • EP3170987B1 patent drawingFigure 3~5

AI summary

The invention relates to an inner ring system (40) with at least one inner ring (12) which is held on at least one guide vane (16) of a turbomachine rotatably mounted about an adjustment axis (14), wherein the inner ring (12) is fixed immovably relative to the at least one guide vane (16) on a radially inner pin (42) of the at least one guide vane (16) in the direction of the adjustment axis (14). The invention further relates to a turbomachine and a method for assembling an inner ring system (40).