Fuel Manifold Purging via Flow Divider for Gas Turbine Engines

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Solution Overview

Problem

Gas turbine engines in twin-engine helicopters operate inefficiently due to the need for both engines to run at all times, limiting fuel efficiency gains and increasing maintenance requirements, especially during cruise phases where only one engine is required.

Innovation Solution

A method and system for operating gas turbine engines with a first and second fuel manifold, where fuel is supplied to the combustor through a flow divider valve, allowing the engine to operate asymmetrically by stopping fuel supply to one manifold and using pressurized gas to flush residual fuel, reducing coking and enabling efficient low-power standby mode operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If both engines are operated at all times during flight, then reliability and safety are improved, but fuel efficiency deteriorates

Engineering Contradiction:

Improveengine reliabilityVSAvoidfuel efficiency

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The fuel supply system is segmented into two separate fuel manifolds (first and second fuel manifolds) with independent flow control. This allows selective operation of individual fuel manifolds, enabling one engine to be put into standby mode while the other operates normally, thereby improving fuel efficiency while maintaining reliability through the capability to rapidly activate the standby engine if needed

Inventive Principle:

Principle #1Segmentation

2Use of energy by moving object

If one engine is stopped during cruise, then fuel efficiency is improved, but the ability to respond to power loss deteriorates

Engineering Contradiction:

Improvefuel efficiencyVSAvoidpower response speed

Core Design Contradiction:

Use of energy by moving objectVSSpeed

Solution Approach 1:

The standby engine's fuel manifold is pre-configured and ready for immediate operation. Pressurized gas is pre-positioned in the system to enable rapid fuel delivery when needed. This preliminary preparation allows the standby engine to transition from idle to full power output almost instantly, maintaining the ability to respond to power loss while enjoying fuel efficiency during normal cruise

Inventive Principle:

Principle #10Preliminary action

3Use of energy by moving object

If fuel supply is stopped to one fuel manifold, then fuel efficiency is improved, but coking in the fuel manifold increases

Engineering Contradiction:

Improvefuel efficiencyVSAvoidcoking

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

Pressurized gas is introduced into the standby fuel manifold to extract and purge residual fuel that would otherwise remain stagnant. This active removal of fuel prevents the chemical reactions that lead to coking, allowing the fuel manifold to be shut off for fuel efficiency without suffering from fuel degradation and carbon deposit formation

Inventive Principle:

Principle #2Taking out (Extraction)

4Object-generated harmful factors

If pressurized gas is supplied to flush fuel in the second fuel manifold, then coking is reduced, but system complexity increases

Engineering Contradiction:

ImprovecokingVSAvoidfuel system complexity

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The pressurized gas system serves multiple functions: it provides purging action to prevent coking in the standby fuel manifold, and it can also support rapid engine restart by ensuring fuel delivery capability. This multi-functionality justifies the added complexity, as the same pressurized gas infrastructure addresses both coking prevention and power response requirements

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 approach enhances fuel efficiency by allowing one engine to operate at high power while the other is in a low-power or standby mode, reducing coking, and enabling rapid power increase in emergency conditions, thus improving overall engine performance and reducing maintenance needs.

Implementation Method 1

supplying pressurized gas to the second fuel manifold via the second flow divider valve to flush fuel in the second fuel manifold into the combustor

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentUS12163474B2System and method for purging a fuel manifold of a gas turbine engine using a flow divider assembly

Publication Date: 2024.12.10 PRATT & WHITNEY CANADA CORP

AI summary

Methods and systems of operating a gas turbine engine in a low-power condition are provided. In one embodiment, the method includes supplying fuel to the combustor by supplying fuel to the first fuel manifold via a first flow divider valve and supplying fuel to the second fuel manifold via a second flow divider valve. While supplying fuel to the combustor by supplying fuel to the first fuel manifold, the method includes stopping supplying fuel to the second fuel manifold and supplying pressurized gas to the second fuel manifold via the second flow divider valve to flush fuel in the second fuel manifold into the combustor and hinder coking in the second fuel manifold and associated nozzles.