Fuel Injector Splitter Divergent Cavities Cooling

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Solution Overview

Problem

Fuel injectors for gas turbine engines face challenges in achieving improved cooling and airflow patterns, particularly in the design of splitter surfaces that are exposed to hot combustion gases, which can lead to inefficiencies in combustion processes.

Innovation Solution

The fuel injector design incorporates a unique splitter surface configuration with divergent portions and connecting surfaces forming cavities, including a first cavity between the first and second splitter surfaces and a second cavity between the second and third splitter surfaces, with openings for fluid communication and circumferential arcuate segments for enhanced airflow and cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If splitter surfaces are exposed to hot combustion gases to enable combustion function, then combustion performance is improved, but the splitter surfaces overheat and require cooling structures

Engineering Contradiction:
Improvecombustion performanceVSAvoidsplitter surface temperature
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The splitter is divided into multiple surfaces (first splitter surface, second splitter surface, third splitter surface) that are separated to form cavities. This segmentation allows different surfaces to serve different functions: outer surfaces exposed to combustion gases for combustion performance, while inner surfaces form cooling cavities. The segmentation enables spatial separation of hot and cool zones within the same component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cavities formed between the splitter surfaces act as intermediary cooling channels. These cavities serve as a mediator between the hot combustion gases and the splitter surfaces, allowing cooling air to flow through and protect the surfaces from overheating while maintaining the combustion function on the outer surfaces.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If cooling structures are added to splitter surfaces, then cooling efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidsplitter structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling structures are merged with the splitter itself rather than being separate components. The cavities are formed by the splitter's own surfaces (first, second, and third splitter surfaces) rather than requiring external cooling channels. This integration reduces device complexity by combining the combustion and cooling functions into a single unified structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The splitter surfaces serve multiple functions simultaneously: the outer surfaces (first and second splitter surfaces) are exposed to combustion gases for combustion performance, while the same surfaces also form the boundaries of cooling cavities for thermal protection. This multi-functionality eliminates the need for separate cooling components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If multiple splitter surfaces are used to form cavities, then cooling and airflow patterns are improved, but manufacturing complexity increases

Engineering Contradiction:
Improveairflow pattern efficiencyVSAvoidsplitter manufacturing complexity
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The multiple splitter surfaces are nested within each other to form hierarchical cavities. The second splitter surface is located radially inward of the first splitter surface, and the third splitter surface is located radially inward of both, creating nested cooling channels. This nested arrangement allows complex airflow patterns to be achieved through a systematic, repeatable structure that simplifies manufacturing compared to arbitrary complex geometries.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 enhances airflow patterns and cooling efficiency, improving combustion performance by maintaining effective airflow through the injector while providing adequate cooling for the splitter surfaces exposed to hot gases.

Implementation Method 1

a first splitter surface having a first divergent portion which is divergent in the downstream direction; a second splitter surface located radially inward of the first splitter surface and having a second divergent portion which is divergent in the downstream direction

Methodology Applied
Scientific EffectDivergent flow:

Implementation Method 2

a first cavity is formed between the first and second splitter surfaces, and the second divergent portion comprises at least one opening in fluid communication with the first cavity

Methodology Applied
Scientific EffectConvection cooling: Convection

Data Source

PatentEP3757462B1Fuel injector
Publication Date: 2023.09.27 ROLLS ROYCE PLC
  • EP3757462B1 patent drawingFigure 1~2
  • EP3757462B1 patent drawingFigure 3~4
  • EP3757462B1 patent drawingFigure 5

AI summary

A fuel injector (44) comprising a first air swirler passage (64) and a second air swirler passage (68) extending axially through the fuel injector and arranged to direct air through the fuel injector, a splitter (70) arranged between the first air swirler passage and the second air swirler passage and comprising a first splitter surface (94) having a first divergent portion (94a) which is divergent in a downstream direction, a second splitter surface (95) located radially inward of the first splitter surface and having a second divergent portion (95a) which is divergent in the downstream direction, a third splitter surface (96) located radially inward of the first and second splitter surfaces, and a first connecting surface (106) extending between the second and third splitter surfaces, wherein a first cavity (91) is formed between the first and second splitter surfaces, and the second divergent portion comprises at least one opening (97) in fluid communication with the first cavity.