Two-Circuit Turbine Injector Combating Blowing Effect

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Solution Overview

Problem

Conventional start-up injectors in turbomachines face issues such as significant blowing effects, which prevent engine starting or restarting at high speeds, and are inefficient due to low fuel flow rates, leading to increased weight and production costs.

Innovation Solution

A combustion chamber injector design with a pre-vaporization fuel injection circuit and a spark plug, where the fuel ignition circuit is enclosed to reduce exposure to air flow, allowing faster ignition and increased fuel flow, enabling engine start-up at any speed and reducing fuel consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional start-up injectors are used with low fuel flow rate, then the engine can be started, but the blowing effect is significant and prevents immediate relighting at high speeds

Engineering Contradiction:
Improveengine starting capabilityVSAvoidblowing effect
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The injector is divided into two separate circuits: a first circuit for starting the combustion chamber and a second circuit for relighting. This segmentation allows each circuit to be optimized for its specific function, with the relighting circuit capable of delivering higher fuel flow rates without being constrained by the starting circuit's low flow rate requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between different fuel injection circuits based on operational requirements. The control unit activates the appropriate circuit (starting circuit for initial ignition, relighting circuit for subsequent ignition) depending on the engine state, enabling optimal performance for each phase of operation.

Inventive Principle:
Principle #15Dynamics

2Productivity

If multiple injectors are positioned over the entire circumference of the bottom wall, then the combustion chamber can be ignited simultaneously, but the engine becomes heavier and more expensive

Engineering Contradiction:
Improvecombustion ignition speedVSAvoidengine weight
Core Design Contradiction:
ProductivityVSWeight of stationary object

Solution Approach 1:

A single injector assembly performs multiple functions by incorporating both a starting injector and a relighting injector with different nozzle configurations. The starting injector has a first nozzle for initial combustion chamber ignition, while the relighting injector has a second nozzle for subsequent ignition, eliminating the need for separate injectors positioned around the combustion chamber circumference.

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

3Ease of operation

If two orifices are made per injector in the combustion chamber and casing, then a nozzle and spark plug can penetrate inside the chamber, but the manufacturing complexity increases

Engineering Contradiction:
Improveinjector functionalityVSAvoidmanufacturing complexity
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The starting injector and relighting injector are merged into a single integrated assembly that functions as one injector unit. This combined assembly requires only a single orifice in the combustion chamber wall and casing, simplifying manufacturing while maintaining the distinct functional capabilities of both starting and relighting operations through internal circuit separation.

Inventive Principle:
Principle #5Merging (Combining)

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

The design mitigates the blowing effect, allows for immediate engine relighting, reduces fuel consumption, and decreases the number of injectors needed, resulting in a lighter, more cost-effective turbomachine with improved fuel efficiency.

Implementation Method 1

a pre-vaporization fuel injection circuit and a spark plug, where the fuel ignition circuit is enclosed to reduce exposure to air flow, allowing faster ignition and increased fuel flow

Methodology Applied
Scientific EffectVaporization: Evaporation

Implementation Method 2

the fuel ignition circuit is enclosed to reduce exposure to air flow, allowing faster ignition and increased fuel flow, enabling engine start-up at any speed

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Implementation Method 3

a pre-vaporization fuel injection circuit and a spark plug, where the fuel ignition circuit is enclosed to reduce exposure to air flow

Methodology Applied
Scientific EffectElectrical discharge ignition: Electric Spark

Data Source

PatentEP2904329B1Two-circuit injector for a turbine engine combustion chamber
Publication Date: 2019.11.27 SAFRAN HELICOPTER ENGINES
  • EP2904329B1 patent drawingFigure 1
  • EP2904329B1 patent drawingFigure 2~3
  • EP2904329B1 patent drawingFigure 4a~4c

AI summary

A start-up injector for a turbine engine combustion chamber, said injector including a fuel injection circuit; and a fuel ignition circuit including a fuel injector supplied by the fuel injection circuit and a spark plug for igniting the injected fuel. The start-up injector also includes a partitioned enclosure including a first compartment in which the fuel is ignited by the spark plug and a second compartment separated from the first compartment by a thermally conductive partition; and a main combustion start-up circuit which includes at least one fuel injector supplied by the fuel injection circuit and opens into the second compartment of the enclosure such as to inject the fuel against the wall.