Gas Turbine Torch Igniter Fuel Circuit Bypass Flowpath

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Solution Overview

Problem

Bypass fuel injectors in gas turbine engines face challenges in fuel control, leading to inaccurate flow regulation, flame instability, component damage, and poor emissions due to parasitic fuel loss and the need for costly hardware or complex control logic.

Innovation Solution

A fuel circuit with a recirculating bypass flowpath that eliminates the need for a sump vessel and associated hardware, using a passive flow regulator to distribute fuel flow based on pressure differences, ensuring accurate and efficient fuel distribution to torch igniters and primary combustors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sump vessel and associated hardware are used to control bypass fuel flow, then fuel flow regulation is achieved, but device complexity and cost increase

Engineering Contradiction:
Improvefuel flow regulation accuracyVSAvoidhardware complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent removes the sump vessel and associated hardware from the fuel system by implementing a recirculating bypass flowpath that eliminates the need for separate fuel collection and regulation components. The bypass flowpath directly recirculates fuel from the bypass injector back to the fuel manifold, simplifying the overall system architecture while maintaining fuel flow control capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The bypass fuel flowpath is designed to automatically recirculate fuel based on pressure differences without requiring external control mechanisms. The system uses the natural pressure gradient between the bypass injector and fuel manifold to drive fuel recirculation, eliminating the need for complex control logic or additional hardware to manage fuel flow.

Inventive Principle:
Principle #25Self-service

2Power

If bypass fuel injectors are used to provide fuel to torch igniter, then fuel delivery capability is improved, but parasitic fuel loss occurs leading to poor emissions and fuel efficiency

Engineering Contradiction:
Improvefuel delivery capabilityVSAvoidparasitic fuel loss
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

Instead of allowing bypass fuel to be lost or wasted, the patent recovers and recirculates it back to the fuel manifold. The recirculating bypass flowpath captures fuel that would otherwise be lost and redirects it to where it can be properly utilized, eliminating parasitic fuel loss and improving overall fuel efficiency.

Inventive Principle:
Principle #34Discarding and recovering

3Measurement precision

If complex control logic is used to manage bypass fuel flow, then fuel distribution accuracy is improved, but ease of operation and system reliability decrease

Engineering Contradiction:
Improvefuel distribution accuracyVSAvoidcontrol logic complexity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system uses automatic pressure-differential-driven recirculation to manage bypass fuel flow without requiring complex control logic. The pressure differences naturally generated during engine operation drive the fuel recirculation process, making the system self-regulating and eliminating the need for sophisticated control algorithms or manual intervention.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The recirculating bypass flowpath creates a feedback mechanism where fuel flow is automatically adjusted based on pressure differences in the system. As fuel pressure changes during engine operation, the recirculation rate automatically adapts to maintain proper fuel distribution, providing continuous self-correcting feedback without external control.

Inventive Principle:
Principle #23Feedback

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 solution simplifies fuel control logic, reduces parasitic losses, and maintains stable flame propagation across a wide range of operating conditions, improving fuel efficiency and emissions performance without the need for heavy or costly hardware.

Implementation Method 1

a pressure difference between the inlet port and the reference port urges the piston against a biasing force of the spring to control fuel flow through the valve to the first and second supply flowpaths

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 2

a biasing force of the spring to control fuel flow through the valve to the first and second supply flowpaths

Methodology Applied
Scientific EffectSpring biasing force: Spring

Data Source

PatentEP3735560B1Gas turbine combustor comprising a torch igniter and method of delivering fuel to a torch igniter
Publication Date: 2022.02.02 WOODWARD INC
  • EP3735560B1 patent drawingFigure 1
  • EP3735560B1 patent drawingFigure 2
  • EP3735560B1 patent drawingFigure 3A~3D

AI summary

A gas turbine combustor assembly (200) includes: a primary combustion chamber (214) in fluid communication with a primary fuel outlet of a primary fuel injector (204); a torch igniter (212) coupled to the primary combustion chamber, the torch igniter including an auxiliary combustion chamber (220) and an auxiliary fuel injector (222) having an auxiliary fuel outlet in fluid communication with the auxiliary combustion chamber; and a fuel circuit including a first supply flowpath (246) between a fuel inlet and the primary fuel injector, a second supply flowpath (250) between the fuel inlet and the auxiliary fuel injector, and a bypass flowpath (252) between the auxiliary fuel injector and the primary fuel injector.