Turbine Exhaust Case Segmentation and Cooling

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Solution Overview

Problem

Turbine exhaust cases in gas turbine engines face challenges in managing high temperatures while maintaining structural support and airflow channeling, as existing materials and architectures often require high-temperature, high-stress capable materials that are costly and complex to produce.

Innovation Solution

A turbine exhaust case design comprising a frame, a vane fairing, a heat shield, and a serpentine cooling path, where the frame is made of cast steel for structural support, the vane fairing and heat shields are made of high-temperature capable nickel-based superalloys, and the serpentine cooling path passes through and around the outer and inner rings and struts to prevent overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-temperature, high-stress capable materials are used to both define the core flow path and bear mechanical loads, then the turbine exhaust case can withstand high temperatures and mechanical loads, but the production cost and manufacturing complexity increase

Engineering Contradiction:

Improveability to withstand high temperatures and mechanical loadsVSAvoidmaterial selection complexity and production cost

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The turbine exhaust case is divided into two functional segments: a structural frame made of cost-effective materials for bearing mechanical loads, and a separate high-temperature capable fairing for defining the core flow path. This segmentation allows each component to be optimized for its specific function, reducing overall material cost while maintaining reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The design employs a composite structure combining different materials with complementary properties: the structural frame uses materials optimized for mechanical strength and cost-effectiveness, while the fairing uses high-temperature resistant materials. This composite approach allows the system to achieve both mechanical reliability and thermal resistance without requiring expensive high-performance materials throughout the entire structure.

Inventive Principle:

Principle #40Composite materials

2Strength

If a structural frame is used to bear mechanical loads, then the turbine exhaust case can support shaft loads, but the frame may overheat without adequate cooling

Engineering Contradiction:

Improvemechanical load bearing capacityVSAvoidframe temperature

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

A heat shield is introduced as an intermediary component between the high-temperature fairing and the structural frame. The heat shield acts as a thermal barrier that protects the frame from excessive heat while allowing the frame to maintain its mechanical load-bearing function. This intermediary element resolves the conflict between mechanical strength requirements and thermal protection needs.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The thermal protection function is extracted from the structural frame and implemented as a separate heat shield component. This allows the frame to be optimized purely for mechanical strength without being constrained by thermal protection requirements, while the heat shield independently handles the thermal protection function.

Inventive Principle:

Principle #2Taking out (Extraction)

3Temperature

If a high-temperature capable fairing is used to define the core flow path, then the core airflow path can be maintained at high temperatures, but the overall structure becomes more complex

Engineering Contradiction:

Improvecore flow path temperature resistanceVSAvoidstructure complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The turbine exhaust case is segmented into distinct functional components: a structural frame for mechanical support and a separate high-temperature fairing for flow path definition. This segmentation allows the fairing to be designed specifically for high-temperature resistance without compromising the structural integrity or increasing overall complexity, as each component is optimized independently for its primary function.

Inventive Principle:

Principle #1Segmentation

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 design effectively manages high temperatures, reducing the risk of overheating and maintaining structural integrity while minimizing production costs and complexity by using a combination of materials and cooling paths to protect the frame from excessive heat.

Implementation Method 1

The serpentine cooling flow path passes through and around the outer ring, the inner ring, and the plurality of struts

Methodology Applied

Scientific EffectForced Convection: Forced Convection

Implementation Method 2

The heat shield is disposed between the vane fairing and the frame

Methodology Applied

Scientific EffectThermal Insulation: Thermal Insulation

Data Source

PatentUS10006306B2Turbine exhaust case architecture

Publication Date: 2018.06.26 RTX CORP

AI summary

A turbine exhaust case (28) for a gas turbine engine (10) comprises a frame (100), a vane fairing (108), a heat shield (124, 126, 128), and a serpentine cooling path. The frame has an outer ring (102) and an inner ring (104) connected by a hollow strut (106) with a radial service line passage (132). The vane fairing is disposed between the inner ring and the outer ring to define a core airflow path. The heat shield is disposed between the vane fairing and the frame. The serpentine cooling flow path passes through and around the outer ring, the inner ring, and the plurality of struts.