Gas Turbine Oil Loop Control for Sustainable Fuel Heat Management

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Solution Overview

Problem

The use of fuels different from traditional kerosene-based jet fuels, such as sustainable aviation fuels, results in different fuel properties, requiring adjustments in gas turbine engine operations to manage heat transfer effectively and improve thermal efficiency.

Innovation Solution

A method and system involving controllable valves in an oil loop system with air-oil and fuel-oil heat exchangers, allowing adjustable oil flow ratios and bypass options to manage heat transfer, and optionally incorporating a refrigeration cycle for thermal lift, tailored to specific fuel characteristics and operating conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional fixed oil flow paths are used, then system simplicity is maintained, but thermal efficiency cannot be optimized for different fuel types

Engineering Contradiction:

Improveadaptability to different fuel typesVSAvoidoil flow control system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements controllable valves (first and second controllable valves) in the oil loop system that enable dynamic adjustment of oil flow ratios through heat exchangers. This allows the system to adapt oil cooling characteristics to match different fuel properties and operating conditions, resolving the contradiction between system simplicity and fuel-type adaptability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of oil flow ratio dynamically based on fuel characteristics and operating conditions. By adjusting the proportion of oil flowing through different heat exchanger paths, the system optimizes heat transfer efficiency for various fuel types without requiring complete system redesign.

Inventive Principle:

Principle #35Parameter changes

2Temperature

If oil flow through heat exchangers is increased to improve cooling, then oil temperature control improves, but heat loss to surroundings increases

Engineering Contradiction:

Improveoil temperature controlVSAvoidheat loss to surroundings

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

The patent applies different oil flow ratios to different heat exchanger paths (air-oil heat exchanger and fuel-oil heat exchanger) based on local requirements. Oil flowing through the fuel-oil heat exchanger transfers heat to fuel (useful heat transfer), while oil through the air-oil heat exchanger transfers heat to air (potential loss). The controllable valves enable selective optimization of each path's heat transfer characteristics.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system converts what would normally be heat loss to air (through the air-oil heat exchanger) into a controllable parameter. By using controllable valves to regulate oil flow, the system can minimize unnecessary heat loss while maintaining effective oil temperature control, turning a potential disadvantage into a manageable parameter.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of energy

If fuel is heated to higher temperatures to improve thermal efficiency, then more heat is transferred to fuel, but deposition of fuel breakdown products increases

Engineering Contradiction:

Improvethermal efficiencyVSAvoidfuel breakdown product deposition

Core Design Contradiction:

Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The system incorporates temperature sensors and controllable valves that enable feedback control of fuel temperature. The controllable valves adjust oil flow ratios based on monitored conditions, preventing fuel temperature from exceeding thresholds that would cause breakdown product deposition, while still maximizing heat transfer within safe limits.

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

Enhances oil cooling and overall thermal efficiency of the engine by allowing fuels to take more heat without significant deposition of breakdown products, reducing heat loss to surroundings, and improving engine performance across various conditions.

Implementation Method 1

a fuel-oil heat exchanger through which the oil in the oil loop system and the fuel flow such that heat is transferred between the oil and the fuel

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

an air-oil heat exchanger through which the oil in the oil loop system flows

Methodology Applied

Scientific EffectHeat transfer: Convection

Data Source

PatentUS20250347250A1Gas turbine temperature sensor

Publication Date: 2025.11.13 ROLLS ROYCE PLC

AI summary

A gas turbine engine includes an engine core including a turbine, compressor, combustor to combust a fuel, and a core shaft connecting the turbine to the compressor; a fan upstream of the engine core; a gearbox that receives an input from the core shaft and outputs drive to the fan to drive the fan; an oil loop system to supply oil to the gearbox; and a heat exchange system with an air-oil heat exchanger through which the oil flows; a fuel-oil heat exchanger through which the oil and the fuel flow; and an air valve to control a flow rate of air through the air-oil heat exchanger. A method of operating the gas turbine engine includes determining at least one fuel characteristic; and controlling the air valve based on the fuel characteristic so as to adjust the flow rate of air through the air-oil heat exchanger.