Aircraft Fuel Recirculation Heating for Cryogenic Turbine Supply
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Solution Overview
Problem
Existing fuel conditioning systems for aircraft turbine engines using cryogenic fuel face issues with increased weight and thermal inertia, requiring bulky and heavy piping due to strict temperature range limitations, which are inefficient and unreliable.
Innovation Solution
A fuel conditioning system with a distribution valve that divides the fuel flow into a direct and recirculated branch, using a first heat exchanger in the aircraft frame and a second in the turbine engine frame to optimize heating, eliminating the need for specialized piping by warming the fuel within the aircraft frame before delivery to the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat transfer fluid circulation loop is used to heat fuel, then the fuel can be heated efficiently, but the piping becomes bulky and heavy due to high thermal inertia and temperature range limitations
Solution Approach 1:
The patent extracts the heat transfer fluid circulation loop from the system and replaces it with a direct fuel recirculation approach. Instead of using a separate heat transfer fluid that requires bulky insulated piping, the system directly recirculates fuel through the heat exchanger, eliminating the need for specialized thermal insulation piping and significantly reducing piping weight.
Solution Approach 2:
The fuel itself serves multiple functions: it is both the substance being heated and the heat transfer medium. By recirculating fuel through the heat exchanger, the system eliminates the need for separate heat transfer fluids and their associated bulky piping infrastructure, achieving weight reduction while maintaining heating efficiency.
2Temperature
If a heat transfer fluid circulation loop is used to heat fuel, then the fuel can be heated, but the aircraft weight increases due to recirculation pump and piping
Solution Approach 1:
The patent removes the heat transfer fluid circulation system including its dedicated recirculation pump and bulky piping. By using fuel recirculation directly through the heat exchanger, the system eliminates these additional components, significantly reducing aircraft weight while preserving fuel heating capability.
Solution Approach 2:
The fuel system serves itself by using the fuel flow to carry out heating functions. The fuel recirculation loop eliminates the need for separate heat transfer fluid systems and their associated pumps and piping, reducing overall system weight while maintaining heating functionality.
3Reliability
If the temperature range of heat transfer fluid is limited, then safety is improved, but the flow rate must increase which leads to larger circulation volume and heavier piping
Solution Approach 1:
The patent eliminates the heat transfer fluid circulation system that is constrained by temperature range limitations. By directly recirculating fuel through the heat exchanger, the system removes the need to manage fluid temperature ranges and their associated safety constraints, thereby avoiding the need for high flow rates and bulky piping.
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 efficiently heats the fuel without the need for heavy insulation pipes, reducing weight and thermal inertia, ensuring reliable operation by maintaining the fuel in a liquid state and avoiding icing risks.
Implementation Method 1
the first heat exchanger being configured to heat the main fuel flow to a circulation temperature
Implementation Method 2
at least one second heat exchanger configured to heat the main fuel flow to at least one injection temperature
Implementation Method 3
the first pump being configured to raise the pressure of the main fuel flow in the fuel circuit to a first pressure
Data Source
AI summary
The invention relates to a conditioning system (SC) for fuel (Q), which is configured to supply an aircraft turbine engine (M) with fuel (Q) from a cryogenic tank (R), the conditioning system (SC) comprising at least one first heat exchanger (31) configured to heat the flow of fuel (Q) to a circulation temperature (Te), at least one second heat exchanger (32) configured to heat the flow of fuel (Q) to an injection temperature (Ti), a distribution valve (4) configured to divide a direct fuel flow (Q1) and a recirculated fuel flow (Q2), configured to circulate in a recirculation branch (12) so as to reheat the main fuel flow (Qp) in the first heat exchanger (31) by means of the recirculated fuel flow (Q2).