Heat Shield Panel Rail Design for Combustor Thermal Expansion

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Solution Overview

Problem

Current heat shield panels in gas turbine engine combustors face challenges in effectively managing thermal protection and accommodating thermal expansion, leading to potential damage from high combustion temperatures and movement constraints.

Innovation Solution

The design incorporates a heat shield panel with a base and rail members that define a cooling chamber, using varying rail thicknesses and configurations to create a boundary wall, which extends from the cold side to the support shell, and includes effusion holes for cooling air to form a protective film on the hot side, while accommodating thermal expansion through strategically placed gaps and attachments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If heat shield panels are used in gas turbine engine combustors to provide thermal protection, then the panels can withstand high combustion temperatures, but the panels are constrained by thermal expansion movements which can lead to potential damage

Engineering Contradiction:

Improvethermal protection capabilityVSAvoidpanel damage risk from thermal expansion

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The heat shield panel is segmented into multiple sections with expansion gaps between them, allowing each segment to expand and contract independently during thermal cycles, thereby reducing stress and preventing damage while maintaining thermal protection

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The panel design incorporates variable thickness regions and asymmetric rail configurations that change geometric parameters to accommodate thermal expansion, allowing the structure to adapt to temperature variations without compromising integrity

Inventive Principle:

Principle #35Parameter changes

2Temperature

If rail members are used to offset the interior of panels from shells to form cooling cavities, then thermal protection is enhanced, but the device complexity increases

Engineering Contradiction:

Improvecooling effectivenessVSAvoidpanel structure complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The rail members serve multiple functions simultaneously: they structurally support the panel, define the cooling cavity geometry, accommodate thermal expansion through asymmetric design, and provide attachment points for effusion holes, thereby reducing overall device complexity despite enhanced cooling capabilities

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The cooling cavity formation is merged with the rail member structure itself, where the rail thickness and configuration directly define the cavity space, eliminating the need for separate cooling channel components and simplifying the overall assembly

Inventive Principle:

Principle #5Merging (Combining)

3Temperature

If effusion holes are used to allow cooling air to form a protective film on the hot side, then thermal protection is improved, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvehot side thermal protectionVSAvoideffusion hole placement and geometry

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The effusion holes are strategically distributed with varying densities and sizes across different regions of the panel, with higher concentration in areas experiencing higher thermal loads, allowing optimized thermal protection without requiring uniform high-precision manufacturing across the entire panel

Inventive Principle:

Principle #3Local quality

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 configuration provides enhanced thermal protection by maintaining a cooling air film on the hot side of the panels, effectively managing thermal expansion and ensuring the structural integrity of the heat shield panels in high-temperature environments.

Implementation Method 1

effusion holes in the panels allow cooling air to reach a hot side of the panels

Methodology Applied

Scientific EffectFilm cooling: Convection

Implementation Method 2

The configuration of the rail members accommodates movement of the panel in a radial direction away from the combustion chamber during thermal expansion

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3604926B1Heat shield panel for use in a gas turbine engine combustor

Publication Date: 2022.10.19 RTX CORP

Figure 1A
Figure 1B~1C
Figure 1D

AI summary

A heat shield panel (300) for use in a gas turbine engine combustor (56) is disclosed. The heat shield panel (300) includes a hot side (230), a cold side (232) spaced from the hot side (230), and a rail (304, 306, 308, 310) disposed about a periphery of the cold side, the rail including a first rail member (308) having a first length (328) extending along the panel, a first height (h) extending from the cold side (232), and a first thickness (350) that varies along the first length (328).