Turbine Containment Case Internal Plenum Cooling

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Solution Overview

Problem

Current gas turbine engine cooling arrangements with external pipes for each turbine stage increase part count and risk of cooling air leakage, leading to thicker, heavier containment cases to manage high temperatures, which is inefficient and weight-intensive.

Innovation Solution

An internal plenum-based cooling arrangement within the containment case of a gas turbine engine, where pressurized air from the compressor is directed into an annular plenum surrounding the turbine stages, providing uniform cooling and reducing thermal stress through an annular plenum between the structural outer case and the containment ring, allowing for thinner construction and reduced weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If multiple external pipes are used to bring coolant to each turbine stage, then cooling coverage is improved, but part count increases and risk of cooling air leakage increases

Engineering Contradiction:
Improvecooling coverageVSAvoidpart count
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

Multiple separate external cooling pipes are merged into a single integrated plenum chamber that distributes coolant to all turbine stages. The plenum acts as a common distribution manifold, eliminating the need for multiple individual pipes while maintaining cooling coverage across all turbine stages.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The plenum chamber serves as an intermediary component between the coolant source and the turbine stages. Instead of directly connecting multiple pipes to each turbine stage, the plenum mediates the coolant distribution, simplifying the overall system architecture while ensuring adequate cooling reach.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If the containment case is made thicker to withstand high temperatures, then structural strength is improved, but weight increases

Engineering Contradiction:
Improvestructural strengthVSAvoidcase weight
Core Design Contradiction:
StrengthVSWeight of stationary object

Solution Approach 1:

Coolant is distributed in advance to the turbine stages through the plenum chamber, pre-cooling the components before they are exposed to high temperatures. This preliminary cooling action allows the containment case to operate at lower temperatures, enabling the use of thinner walls while maintaining structural strength.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The thermal parameters of the containment case are changed by actively cooling the turbine stages within it. By reducing the temperature of the turbine stages through coolant distribution, the thermal load on the containment case is reduced, allowing for optimized wall thickness that balances strength requirements with weight reduction.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If external pipes are used for cooling, then cooling delivery is improved, but reliability decreases due to increased leakage risk

Engineering Contradiction:
Improvecooling deliveryVSAvoidcooling system reliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

Multiple separate cooling pipe connections are merged into a single plenum chamber system. This consolidation reduces the total number of potential leakage points from multiple pipe joints to fewer connections at the plenum, thereby improving the reliability of the cooling system while maintaining effective cooling delivery.

Inventive Principle:
Principle #5Merging (Combining)

4Temperature

If multiple external pipes are used, then cooling distribution is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvecooling distributionVSAvoidmanufacturing complexity
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The manufacturing process is simplified by consolidating multiple separate pipe fabrication and installation tasks into a single plenum chamber fabrication. The plenum can be manufactured as one integrated component with internal flow passages, reducing the number of manufacturing steps, joints, and assembly operations required compared to installing multiple individual external pipes.

Inventive Principle:
Principle #5Merging (Combining)

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 reduces thermal-induced stress and weight by uniformly distributing coolant, minimizing the need for external pipes and improving blade tip clearance, while maintaining structural integrity and reducing part count.

Implementation Method 1

pressurized air from the compressor is directed into an annular plenum surrounding the turbine stages, providing uniform cooling

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

reducing thermal stress through an annular plenum between the structural outer case and the containment ring

Methodology Applied
Scientific EffectThermal stress reduction: Thermal Expansion

Data Source

PatentEP3192982B1Cooled containment case using internal plenum and method
Publication Date: 2021.12.15 PRATT & WHITNEY CANADA CORP
  • EP3192982B1 patent drawingFigure 1
  • EP3192982B1 patent drawingFigure 2
  • EP3192982B1 patent drawingFigure 3

AI summary

A case assembly (100) for a turbine section has a structural outer case (108) structurally connected to a gas generator upstream of the outer case (108) and to an exhaust case (102) downstream of the outer case (108). The assembly (100) further comprises a containment ring (110) mounted within the outer case (108) and surrounding a plurality of axially spaced-apart turbine stages (S1,S2,S3). An inner surface of the containment ring (110) defines a plurality of shroud receiving portions (110C). An annular plenum (112) is defined between the outer case (108) and the containment ring (110). The plenum (112) has an inlet connected to a source of pressurized coolant. Outlets are circumferentially and axially distributed and defined through the containment ring (110). The outlets provides flow communication between the annular plenum (112) and the plurality of axially spaced-apart turbine stages (S1,S2,S3).