Floating Seal Assembly for Turbomachine Clearance Control

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Solution Overview

Problem

Existing sealing assemblies in turbomachines are not effective at all operating conditions, particularly during transient conditions, as they rely on steady-state thermal expansion for optimal performance, leading to inefficiencies and increased risk of rub conditions due to varying clearances caused by temperature changes.

Innovation Solution

A sealing arrangement featuring a floating seal with axial and radial members, coupled with magnets, that maintains alignment and separation between stationary and rotating components, preventing leakage and contact, thus maintaining efficiency across varying operating conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the clearance between rotary and stationary components is reduced to improve performance and efficiency, then fluid leakage between blades and shroud decreases, but the potential for rub conditions increases

Engineering Contradiction:

Improvefluid leakageVSAvoidrub condition risk

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

A sealing assembly is introduced as an intermediary component between the rotary and stationary components. The sealing assembly includes a seal member that actively maintains a controlled clearance, preventing direct contact (rub conditions) while restricting fluid leakage through the clearance zone.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces passive mechanical clearance control with an active sealing assembly that uses a combination of mechanical elements (seal member, support structure) and fluid dynamics to maintain optimal clearance dynamically, allowing the system to adapt to varying operating conditions without requiring fixed tight tolerances.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a sealing assembly is used to restrict flow through clearance, then sealing effectiveness improves at steady state, but performance deteriorates during transient conditions due to thermal expansion variations

Engineering Contradiction:

Improvesealing effectivenessVSAvoidperformance across operating conditions

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The sealing assembly is designed with dynamic characteristics, where the seal member can move axially within its clearance zone to adapt to changing thermal expansion conditions. The support structure allows controlled movement while maintaining sealing effectiveness across varying temperatures and operating conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The sealing assembly exploits changes in thermal expansion parameters to its advantage. As the rotary and stationary components expand differently with temperature changes, the sealing assembly adjusts its position and clearance characteristics to maintain effective sealing, rather than relying on fixed geometric relationships.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the clearance increases during transient conditions due to thermal expansion, then rub conditions are prevented, but performance and efficiency decrease due to increased fluid leakage

Engineering Contradiction:

Improverub condition preventionVSAvoidturbomachine efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The sealing assembly acts as an intermediary that fills and controls the clearance zone between rotary and stationary components. Even when thermal expansion increases the physical clearance, the seal member maintains a restricted flow path through its geometry, preventing excessive leakage while allowing the components to expand without contact.

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

The solution effectively reduces leakage and minimizes the risk of frictional wear by maintaining a consistent seal across all operating conditions, enhancing turbomachine efficiency and prolonging seal life through magnetic repulsion, which keeps the floating seal aligned and separated from the components.

Implementation Method 1

magnetic repulsion, which keeps the floating seal aligned and separated from the components

Methodology Applied

Scientific EffectMagnetic repulsion: Ion Repulsion/Attraction

Data Source

PatentUS11248531B1Turbomachine clearance control using a floating seal

Publication Date: 2022.02.15 GE INFRASTRUCTURE TECH LLC

AI summary

A sealing arrangement includes a stationary component, a first slot is defined between an outer wall and a first inner wall, a second slot is defined between the outer wall and a second inner wall. A rotating component moves in a circumferential direction relative to the stationary component. The rotating component includes a tip rail. A floating seal positioned between the stationary component and the rotating component. The floating seal includes an axial member having a first arm extending into the first slot and a second arm extending into the second slot. The floating seal includes a first radial member and a second radial member that extends from the axial member. A plurality of magnets coupled to the stationary component, the rotating component, and the floating seal. The plurality of magnets is arranged such that the floating seal is contained between the stationary component and the rotating component.