Turbine Case Cooling Manifold with Adjustable Flow Restrictors

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Solution Overview

Problem

Gas turbine engines face efficiency reduction due to leakage between turbine blades and shrouds caused by differential thermal expansion, which can lead to component damage from contact, necessitating controlled clearance maintenance.

Innovation Solution

A turbine case cooling system with a manifold and adjustable flow restrictors and valves to control fluid flow for thermal resizing of the turbine casing, allowing precise management of clearance space between blade tips and shrouds during different engine operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a two stop valve is used to control air flow to the casing, then the flow can be adjusted for different engine operations, but the device complexity increases

Engineering Contradiction:

Improveflow control for different engine operationsVSAvoidvalve configuration complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The air supply system is segmented into multiple independent inlet passages, each with its own flow restrictor. This allows different air flows to be controlled separately for different engine operations without requiring a complex two-stop valve mechanism.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Flow restrictors are introduced as intermediary elements between the air supply and the casing cooling system. These restrictors provide precise flow control through their physical geometry rather than requiring complex valve mechanisms.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If impingement cooling holes are used to meter and restrict air flow, then flow control is achieved, but the device complexity and flow restriction limitations increase

Engineering Contradiction:

Improveflow metering capabilityVSAvoidcooling system structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The flow control function is extracted from the cooling holes and implemented through dedicated flow restrictors in separate inlet passages. This simplifies the cooling system structure while maintaining precise flow metering capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The flow restrictors serve multiple functions: they control air flow rate, simplify valve requirements, and enable quick tuning for different operations. This multi-functionality reduces overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Manufacturing precision

If the turbine casing is cooled to maintain clearance, then thermal resizing is achieved, but the risk of improper flow control increasing

Engineering Contradiction:

Improveclearance control precisionVSAvoidflow control reliability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The flow restrictors are designed with fixed geometric features that automatically provide the correct flow restriction for each inlet passage. This self-service approach eliminates the need for complex control mechanisms and reduces the risk of improper flow control.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Different flow restrictors with different geometric parameters can be selected and installed in different inlet passages to achieve the desired flow distribution for various engine operations, ensuring reliable clearance control.

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

Enables quick tuning and improved flow control, reducing complexity and risk, and allowing on-wing adjustments to maintain optimal clearance, thereby enhancing turbine efficiency and component lifespan.

Implementation Method 1

the cooling system is arranged to deliver the cooling fluid to a radially outer surface of the turbine casing whereby the turbine casing is cooled and contracts radially inwardly

Methodology Applied

Scientific EffectThermal contraction: Thermal Contraction

Implementation Method 2

the resizing system may be arranged to deliver a heating fluid from an upstream source through the manifold and outlets to the radially outer surface of the turbine casing whereby the turbine casing is heated and expands radially outwardly

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10669879B2Controlling tip clearance in a turbine

Publication Date: 2020.06.02 ROLLS ROYCE PLC

AI summary

A turbine case cooling system comprises a manifold (21) radially adjacent a portion of a radially outer surface of the turbine case (26) and in fluid communication with one or more of radially inwardly directed outlets (25). The manifold (21) has a first inlet (22) and a second inlet (23). The first inlet (22) is obstructed by a first flow restrictor (22a) and the second inlet (23) is obstructed by a second flow restrictor (23a). The first inlet (22) includes a valve (24) upstream of the first flow restrictor (22a) and the valve is adjustable to control flow of fluid supply entering the first inlet (22).