Combustor Dome Heat Shield with Notch Cavity Cooling

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Solution Overview

Problem

Existing heat shields in gas turbine engine combustors face challenges in minimizing coolant usage while maintaining effective cooling and reducing emissions, as they are exposed to hot gases and suffer from coolant leakage issues.

Innovation Solution

A dome heat shield design featuring a heat shield panel with rails and anti-rotation notches that direct cooling air to targeted areas, minimizing leakage by capturing escaping air into notch cavities and enhancing cooling efficiency through strategic air flow management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If coolant is used to cool the heat shield, then the heat shield can withstand high temperatures, but coolant leakage occurs and combustion efficiency decreases

Engineering Contradiction:

Improveheat shield temperatureVSAvoidcombustion efficiency

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

The heat shield is divided into multiple panels with individual cooling channels, allowing localized cooling control. Each panel can be independently cooled, preventing excessive coolant usage while maintaining temperature control in critical areas.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Cooling channels are strategically positioned in areas requiring cooling based on thermal load analysis. The cooling intensity varies by location, applying coolant only where necessary to maintain structural integrity without over-cooling and improving combustion efficiency.

Inventive Principle:

Principle #3Local quality

2Reliability

If rails are added to the heat shield panel, then cooling air flow is improved, but device complexity increases

Engineering Contradiction:

Improvecooling air flowVSAvoidheat shield structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The rails serve multiple functions: they provide structural support for the heat shield panel, act as flow distributors for cooling air, and serve as mounting features for anti-rotation notches. This multi-functionality reduces the need for separate components, maintaining reliability while limiting complexity increase.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The cooling air distribution function is merged into the structural rails themselves. The rails are designed with internal passages and external geometry that simultaneously provide structural integrity and optimized coolant flow distribution, eliminating the need for separate flow distribution components.

Inventive Principle:

Principle #5Merging (Combining)

3Stability of the object's composition

If anti-rotation notches are defined in the rails, then anti-rotation capability is provided, but coolant leakage paths are created

Engineering Contradiction:

Improveanti-rotation capabilityVSAvoidcoolant leakage

Core Design Contradiction:

Stability of the object's compositionVSLoss of substance

Solution Approach 1:

A seal element is introduced as an intermediary component between the anti-rotation notch and the external environment. This seal prevents coolant leakage through the notch while allowing the notch to perform its anti-rotation function, thus maintaining both stability and preventing substance loss.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Flexible seal lips or thin film seals are positioned within the anti-rotation notches to prevent coolant leakage. These flexible elements conform to the notch geometry and block leakage paths while allowing the necessary rotational constraint function to operate.

Inventive Principle:

Principle #30Flexible shells and thin films

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 reduces coolant air leakage, enhances cooling efficiency, and minimizes emissions by optimizing air flow and heat transfer, thereby improving combustion efficiency and reducing smoke, unburned hydrocarbon, and CO/NOx emissions.

Implementation Method 1

the notch cavity rails defining a notch cavity in fluid flow communication with the anti-rotation notch

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 2

a heat shield panel adapted to be mounted to a combustor dome with a back face of the heat shield panel in spaced-apart facing relationship with an inner surface of the combustor dome to define an air gap

Methodology Applied

Scientific EffectHeat transfer:

Data Source

PatentUS9933161B1Combustor dome heat shield

Publication Date: 2018.04.03 PRATT & WHITNEY CANADA CORP

AI summary

A combustor dome heat shield has a heat shield panel adapted to be mounted to a combustor dome with a back face of the heat shield panel in spaced-apart facing relationship with an inner surface of the combustor dome to define an air gap between the heat shield panel and the combustor dome. Rails extend from the back face of the heat shield panel across the air gap. An anti-rotation notch is defined in at least one of the rails for receiving an anti-rotation tab of an adjacent element, such as a fuel nozzle floating collar. The rails include notch cavity rails extending on either side of the anti-rotation notch. The notch cavity rails define a notch cavity for capturing coolant air leaking through the anti-rotation notch.