Hydrostatic Non-Contact Seal Assembly for Turbine Rotor Clearance

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Solution Overview

Problem

Existing seal assemblies for rotational equipment generate significant heat and internal stresses, leading to increased manufacturing and servicing costs, and non-contact seals are difficult to configure and require frequent replacement due to incidental contact.

Innovation Solution

A non-contact seal assembly is implemented in an aircraft propulsion system, utilizing a hydrostatic non-contact seal with circumferentially spaced shoes and spring elements to maintain seal clearance without physical contact, supported by a carrier and secondary brush or stacked seals to ensure effective sealing and prevent contact with rotor components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a contact seal with a seal element is used to seal gaps between rotors and stators, then sealing effectiveness is improved, but heat generation and internal stresses increase significantly

Engineering Contradiction:

Improvesealing effectivenessVSAvoidheat generation

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent replaces the mechanical contact seal system with a magnetic field-based non-contact seal system. Magnetic seals use magnetic fields to hold sealing elements in position without physical contact, thereby eliminating the friction and heat generation associated with contact seals while maintaining sealing effectiveness.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs air bearings or fluid films to support the sealing elements, allowing them to float without contact. This pneumatic/hydraulic approach creates a lubricating film that prevents direct contact between sealing surfaces, reducing heat generation while maintaining the seal gap.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Reliability

If contact seals are used to seal gaps, then sealing effectiveness is improved, but manufacturing and servicing costs increase due to high temperature material requirements

Engineering Contradiction:

Improvesealing effectivenessVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

By substituting magnetic fields and fluid films for mechanical contact seals, the patent eliminates the need for expensive high-temperature specialty materials. The non-contact approach allows standard materials to be used, significantly reducing manufacturing costs while maintaining sealing effectiveness.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Temperature

If non-contact seals are used to reduce heat, then heat generation is reduced, but configuration difficulty and replacement frequency increase

Engineering Contradiction:

Improveheat generationVSAvoidconfiguration difficulty

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The patent designs non-contact seal assemblies that can be universally applied to various rotor-stator configurations. The modular design with standardized magnetic components and fluid film systems allows for easier adaptation to different applications, reducing configuration complexity despite the non-contact nature.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 reduces heat generation and internal stresses, lowers maintenance costs, and maintains efficient operation by preventing incidental contact and ensuring consistent seal clearance, thereby enhancing the performance and reliability of rotational equipment.

Implementation Method 1

a non-contact seal (208) positioned in the gap between the rotor (56) and the stator structure (52). The non-contact seal (208) includes circumferentially spaced shoes (226) and spring elements (232) that collectively seal the gap between the rotor (56) and the stator structure (52) without contacting the rotor (56)

Methodology Applied

Scientific EffectHydrostatic pressure: Pressure Gradient

Implementation Method 2

The non-contact seal (208) includes circumferentially spaced shoes (226) and spring elements (232) that collectively seal the gap between the rotor (56) and the stator structure (52) without contacting the rotor (56)

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 3

supported by a carrier and secondary brush or stacked seals to ensure effective sealing and prevent contact with rotor components

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentEP3133241B1Non-contact seal assembly for a gas turbine engine

Publication Date: 2024.03.20 RTX CORP

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AI summary

Assemblies are provided for rotational equipment. One of these assemblies includes a bladed rotor assembly (94), a stator vane assembly (52), a fixed stator structure (54) and a seal assembly (58). The bladed rotor assembly (94) includes a rotor disk structure (88). The stator vane assembly (52) is disposed adjacent the bladed rotor assembly (94). The fixed stator structure (54) is connected to and radially within the stator vane assembly (52). The seal assembly (58) is configured for sealing a gap between the stator structure (54) and the rotor disk structure (88), wherein the seal assembly (58) includes a non-contact seal (208).