Isochoric Fuel Compression Modules for Cryogenic Turbine Engines

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Solution Overview

Problem

Existing fuel packaging systems for aircraft turbomotors powered by cryogenic fuel face inefficiencies and reliability issues due to the use of mechanical pumps, which require significant energy and are not adaptable to a wide range of flow/pressure conditions.

Innovation Solution

A fuel packaging system that includes a buffer tank and multiple compression modules, each comprising an elementary fixed volume tank, an elementary heat source for isochore compression, and valves for input, output, and degassing, allowing for efficient compression and heating of fuel without relying solely on mechanical pumps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a mechanical pump is used to pressurize fuel from a cryogenic tank, then the fuel can be supplied to the turbine engine, but the system requires significant energy and has limited adaptability to flow/pressure conditions

Engineering Contradiction:
Improvefuel pressurization capabilityVSAvoidenergy consumption
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The patent replaces the mechanical pump with a thermodynamic compression system using compressors and heat exchangers. Instead of using mechanical displacement to pressurize fuel, the system uses gas compression and heat transfer to achieve the same result, thereby eliminating the energy inefficiencies and adaptability limitations of mechanical pumps

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the thermodynamic parameters (temperature and pressure) of the fuel through controlled heating and compression processes. By adjusting these parameters independently, the system can adapt to a wide range of flow and pressure conditions without being constrained by a fixed mechanical pump operating point

Inventive Principle:
Principle #35Parameter changes

2Power

If a mechanical pump is used to pressurize fuel, then fuel can be delivered to the engine, but the pump operates at a non-optimal point requiring constraints that reduce efficiency

Engineering Contradiction:
Improvefuel delivery capabilityVSAvoidoperational efficiency
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The system introduces dynamic control of compression and heating processes, allowing independent adjustment of pressure and temperature parameters. This enables the system to operate at optimal points across varying conditions, unlike a fixed mechanical pump that must operate away from its optimal range

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent divides the fuel pressurization process into separate compression and heating stages, each optimized for its specific function. This segmentation allows each component to operate at its optimal efficiency point while collectively achieving the required fuel delivery performance

Inventive Principle:
Principle #1Segmentation

3Power

If a mechanical pump is used for fuel compression, then fuel can be pressurized, but sealing and lubrication become problematic in cryogenic conditions

Engineering Contradiction:
Improvefuel compression capabilityVSAvoidsealing and lubrication performance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent eliminates mechanical contact components (pump seals and lubrication systems) by replacing the mechanical pump with a thermodynamic compression system. The compressors and heat exchangers used in the alternative system have fewer moving parts and do not require the same sealing and lubrication mechanisms, thereby improving reliability in cryogenic conditions

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 system achieves better yield and reliability by using isochore compression and available heat sources, maintaining optimal fuel conditions for the turbomotor, and reducing the need for high-pressure pumps, thus enhancing energy efficiency and operational flexibility.

Implementation Method 1

an elementary heat source configured to increase the temperature of the fuel in the elementary tank in an isochoric manner

Methodology Applied
Scientific EffectIsochoric heating: Heating

Implementation Method 2

When degassing an elementary tank, the gas stream expands isenthalpically in the cryogenic tank, thereby balancing the pressures to allow a new safe cycle of use

Methodology Applied
Scientific EffectIsenthalpic expansion: Joule-Thomson Effect

Data Source

PatentEP4355986B1Fuel conditioning system and method configured to supply an aircraft turbine engine with fuel from a cryogenic tank
Publication Date: 2025.04.09 SAFRAN SA
  • EP4355986B1 patent drawingFigure 1
  • EP4355986B1 patent drawingFigure 2
  • EP4355986B1 patent drawingFigure 3~4A

AI summary

A fuel conditioning system configured to supply an aircraft turbine engine with fuel from a cryogenic tank, the fuel circuit comprising a buffer tank (R2) for supplying the turbine engine and a plurality of compression modules (1A-1D) configured to supply the buffer tank (R2), each compression module (1A-1D) comprising an elementary tank (3A-3D) of fixed volume, an elementary heat source (2A-2D) configured to increase the temperature of the fuel in the elementary tank (3A-3D) in an isochoric manner, an inlet valve (V1A-V1D) connecting the elementary tank (3A-3D) to an upstream part of the fuel circuit (CQ), an outlet valve (V3A-V3D) connecting the elementary tank (3A-3D) to the buffer tank (R2) and a venting valve (V3A-V3D) connecting the elementary tank (3A-3D) to the cryogenic tank via a return circuit (CR) in which a gaseous stream (G) circulates.