Fuel Calorific Value Determination for Gas Turbine Weight Optimization

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Solution Overview

Problem

The aviation industry faces inefficiencies in managing and optimizing fuel usage in aircraft propulsion systems due to the lack of precise control over fuel characteristics, particularly calorific value, which affects flight performance and fuel weight, especially with the trend towards using fuels different from traditional kerosene-based jet fuels.

Innovation Solution

A method and system for determining the calorific value of available fuel on an aircraft, involving obtaining energy requirements for a flight profile, calculating the necessary fuel amount, and refueling accordingly, using techniques such as input data, chemical, and physical determination methods, including tracer identification and sensor monitoring, to ensure efficient fuel management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the aircraft carries sufficient fuel for the intended flight with a safety margin, then the flight safety is improved, but the take-off weight increases due to excess fuel

Engineering Contradiction:

Improveflight safetyVSAvoidtake-off weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The system changes the parameter of fuel quantity by calculating the precise amount needed based on the actual calorific value of the fuel. Instead of using a fixed safety margin, the system dynamically adjusts the fuel quantity to match the actual energy content, thereby reducing excess weight while maintaining safety.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system replaces the traditional mechanical approach of filling fuel tanks to fixed capacity or using conservative estimates with an electronic/digital system that measures the actual calorific value and calculates the precise fuel quantity needed, substituting physical intuition with scientific measurement and computation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If traditional kerosene-based jet fuels are used, then the fuel management is simplified, but the adaptability to new fuel types is reduced

Engineering Contradiction:

Improvefuel management simplicityVSAvoidfuel type adaptability

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The system is designed to accommodate different fuel types by measuring and adapting to their specific calorific values. The fuel management system dynamically adjusts calculations and controls based on the actual fuel characteristics, enabling seamless operation with various fuel types while maintaining simplicity through automated adaptation.

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If fuel with higher calorific value is used, then the fuel quantity needed is reduced, but the measurement and control precision requirements increase

Engineering Contradiction:

Improvefuel quantityVSAvoidcalorific value measurement precision

Core Design Contradiction:

Quantity of substanceVSMeasurement precision

Solution Approach 1:

The system replaces manual or approximate fuel quantity estimation with automated electronic measurement and calculation systems that precisely determine calorific values and compute the exact fuel quantity needed, thereby achieving high measurement precision through digital technology rather than mechanical methods.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system incorporates feedback mechanisms where the measured calorific value is continuously used to adjust and verify fuel quantity calculations. This feedback loop ensures that the fuel quantity is precisely controlled based on actual fuel characteristics, maintaining accuracy throughout the fuel management process.

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 approach allows for more efficient fuel control, reducing take-off weight by optimizing fuel load based on calorific value, improving aircraft performance and safety by ensuring sufficient energy for flights while minimizing excess fuel weight.

Implementation Method 1

a gas turbine engine; a fuel tank arranged to contain fuel to power the gas turbine engine

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 2

chemically and/or physically determining the calorific value of the available fuel

Methodology Applied

Scientific EffectCalorimetry: Calorimetry

Data Source

PatentUS12158438B2Method of determining the calorific value of fuel provided to a gas turbine engine

Publication Date: 2024.12.03 ROLLS ROYCE PLC

AI summary

A method of checking refuelling of an aircraft comprising a gas turbine engine and a fuel tank arranged to provide fuel to the gas turbine engine comprises: receiving an input of calorific value data for fuel provided to the aircraft on refuelling; independently determining at least one of: (i) the calorific value of fuel supplied to the gas turbine engine in use; and (ii) the calorific value of the fuel provided to the aircraft on refuelling; and providing an alert if the determined calorific value is inconsistent with the calorific value data input received.