Combustor Reverse Dilution Air Mixing

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Solution Overview

Problem

Existing gas turbine engine combustors, particularly RQL combustors, face challenges in achieving further reduction of NOx emissions due to incomplete mixing of dilution air with combustion gases, which limits the effectiveness of the combustion process.

Innovation Solution

The design incorporates a compact combustor architecture with a forward liner segment defining a primary combustion chamber and an aft liner segment defining a secondary combustion chamber, featuring channels oriented to direct dilution air in a counter-flow direction to the combustion gases, enhancing turbulence and mixing within the combustion gases upstream of the secondary combustion chamber.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If dilution air is introduced in conventional direction, then combustion process is maintained, but mixing of dilution air with combustion gases is incomplete

Engineering Contradiction:

Improvemixing completenessVSAvoidcombustor configuration

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent applies reverse flow dilution air introduction, where dilution air is injected opposite to the direction of combustion gas flow. This inversion of the conventional approach creates counter-flow mixing that significantly enhances mixing completeness between dilution air and combustion gases, directly resolving the technical contradiction.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces dilution air through channels formed between liner segments, creating a three-dimensional counter-flow mixing zone. This dimensional approach to dilution air introduction improves mixing effectiveness by utilizing the spatial configuration between forward and aft liner segments, rather than simple linear injection.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-generated harmful factors

If RQL combustion method is used, then NOx formation is reduced, but mixing of dilution air with combustion gases remains insufficient

Engineering Contradiction:

ImproveNOx emissionsVSAvoiddilution air mixing

Core Design Contradiction:

Object-generated harmful factorsVSQuantity of substance

Solution Approach 1:

By reversing the flow direction of dilution air injection, the patent enhances the mixing effectiveness within the RQL combustion process. The counter-flow introduction ensures more complete interaction between dilution air and combustion gases, thereby improving NOx reduction effectiveness while maintaining the RQL combustion methodology.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent utilizes fluid dynamic principles by introducing dilution air through channels between liner segments, creating controlled counter-flow patterns. This pneumatic approach leverages the interaction between opposing gas flows to achieve enhanced mixing and more effective NOx reduction in the RQL combustion process.

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Quantity of substance

If channels are oriented to direct dilution air in counter-flow direction, then mixing is enhanced, but device complexity increases

Engineering Contradiction:

Improvemixing completenessVSAvoidchannel configuration

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent utilizes the existing segmentation of the combustor into forward and aft liner segments to create the counter-flow channels. By orienting channels between these segments to direct dilution air opposite to combustion gas flow, the design enhances mixing while leveraging the already-segmented structure, thereby limiting the increase in device complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The channels between liner segments serve multiple functions: they provide structural support for the liner segments, define the combustion chamber geometry, and simultaneously act as flow paths for counter-flow dilution air injection. This multi-functionality reduces the need for additional dedicated mixing components, limiting the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 results in more complete mixing of dilution air and combustion gases, leading to greater NOx reduction and improved operability, providing a more stable combustion process with reduced NOx emissions.

Implementation Method 1

enhancing turbulence and mixing within the combustion gases upstream of the secondary combustion chamber

Methodology Applied

Scientific EffectTurbulence: Turbulence

Data Source

PatentUS11835236B1Combustor with reverse dilution air introduction

Publication Date: 2023.12.05 GENERAL ELECTRIC CO

AI summary

A combustor for a gas turbine engine includes a forward liner segment having an aft end portion. The forward liner segment at least partially defines a primary combustion chamber. The combustor further includes an aft liner segment having a forward end portion. A channel is defined between the forward liner segment and the aft liner segment. The channel directs a stream of dilution air in a counter-flow or reverse direction with respect to combustion gases flowing from the primary combustion chamber during operation of the combustor.