Gas Turbine Combustor Segmented Air-Fuel Mixing

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Solution Overview

Problem

Existing gas turbine combustors face challenges in precisely controlling the fuel-air ratio, leading to unstable combustion and increased NOx emissions, particularly during partial load operations due to air-fuel mixture dilution between perforated plates.

Innovation Solution

The design incorporates a burner configuration with a base plate and turning plate, featuring partitioned internal channels and oblique air holes to prevent dilution, allowing precise control of the fuel-air ratio and promoting stable combustion while reducing NOx emissions through staged fuel injection and mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If air holes are provided in perforated plates for air-fuel mixing, then premix combustion is achieved and NOx emission is reduced, but air-fuel mixture is diluted between plates and fuel-air ratio control precision deteriorates

Engineering Contradiction:
ImproveNOx emissionVSAvoidfuel-air ratio control precision
Core Design Contradiction:
Object-generated harmful factorsVSMeasurement precision

Solution Approach 1:

The air hole plate is divided into multiple independent air hole units, each corresponding to a specific fuel nozzle. This segmentation prevents air from adjacent fuel nozzles from mixing and diluting the air-fuel mixture in the internal channel, thereby maintaining precise fuel-air ratio control while still achieving premix combustion for NOx reduction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each air hole unit is designed with localized air supply corresponding to its associated fuel nozzle. The air holes are positioned and sized to provide the exact amount of air needed for that specific fuel injection, creating locally optimized air-fuel mixing zones that prevent dilution while achieving complete premix combustion.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If fuel is injected from part of fuel nozzles for partial load operation, then operation flexibility is improved, but air-fuel mixture dilution occurs and combustion stability deteriorates

Engineering Contradiction:
Improveoperation flexibilityVSAvoidcombustion stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The burner system is segmented into multiple independently controllable fuel nozzle units, each with its own air hole unit and internal channel. This allows selective activation of specific fuel nozzles for partial load operation while preventing air-fuel mixture dilution through the segmented architecture, thereby maintaining combustion stability across all operating conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts the number of active fuel nozzle units based on load requirements. Each unit maintains its dedicated air supply path, ensuring that even when operating with fewer units, the air-fuel mixture remains undiluted and combustion stability is preserved throughout the operational range.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If multiple air hole rows are arranged concentrically, then air-fuel mixing is promoted, but structure complexity increases

Engineering Contradiction:
Improveair-fuel mixing efficiencyVSAvoidburner structure complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The air hole plate design integrates multiple air hole rows into a single universal component that serves all fuel nozzle units. Each air hole unit within the plate performs the same function (providing air for its corresponding fuel nozzle) while the concentric arrangement promotes air-fuel mixing. This multi-functional design achieves effective mixing without proportionally increasing structural 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 enables stable combustion from ignition to full load operations while minimizing NOx emissions by ensuring accurate fuel-air mixing and reducing pressure loss, enhancing the reliability and efficiency of the gas turbine plant.

Implementation Method 1

an air-fuel mixture jet is supplied to a combustion chamber and the air-fuel mixture is mixed and combusted in the combustion chamber

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

a fuel jet and an air jet are ejected into an internal channel and the fuel jet and the air jet are mixed together

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3067625B1Gas turbine combustor, gas turbine and method
Publication Date: 2019.06.19 MITSUBISHI HITACHIPOWER SYST LTD
  • EP3067625B1 patent drawingFigure 1
  • EP3067625B1 patent drawingFigure 2
  • EP3067625B1 patent drawingFigure 3~4

AI summary

A gas turbine combustor 2 according to the present invention comprises: a combustion chamber 50 in which fuel is burned with air to generate combustion gas; a plurality of fuel nozzles 30 arranged in multiple concentric annular rows; a first plate 32 arranged downstream of the fuel nozzles 30 and having multiple concentric circular air hole rows made up of a plurality of air holes corresponding to the fuel nozzles 30; a second plate 33 arranged downstream of the first plate 32 and having multiple air hole rows corresponding to the air hole rows of the first plate 32; and a partition wall part 37 which partitions a space part 46 between the first plate 32 and the second plate 33 into rooms corresponding to the air hole rows.