A thermal management system for an aircraft
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Solution Overview
Problem
Conventional thermal management systems for aircraft gas turbine engines struggle to meet cooling demands during sub-idle engine operation and post-shutdown conditions, leading to high fuel temperatures and potential component malfunctions, especially in lean burn fuel systems, due to insufficient heat sinks and thermal inertia.
Innovation Solution
A thermal management system incorporating a first thermal bus with a chiller and vapour compression system, where waste heat from the gas turbine engine and ancillary systems is transferred to a heat transfer fluid, and the vapour compression system raises the temperature of lower-temperature waste heat to match or exceed the heat transfer fluid temperature, enhancing heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If waste heat from ancillary systems is transferred directly to the first heat transfer fluid, then heat transfer occurs, but the temperature differential is insufficient when ancillary system heat is cooler than the first heat transfer fluid
Solution Approach 1:
The patent introduces a second heat transfer fluid and a vapour compression system as an intermediary between the ancillary systems and the first heat transfer fluid. The second fluid absorbs heat from ancillary systems, and the vapour compression system raises its temperature before transferring to the first fluid, enabling efficient heat transfer across temperature gradients
Solution Approach 2:
The patent changes the temperature parameter of the second heat transfer fluid dynamically using a vapour compression system. By adjusting the temperature of the intermediate fluid based on operating conditions, the system optimizes heat transfer efficiency between ancillary systems and the main thermal bus
2Use of energy by moving object
If fuel flow is reduced during low-power conditions, then fuel consumption decreases, but fuel temperature rises causing deposits and component failures
Solution Approach 1:
The patent converts the waste heat from ancillary systems, which would otherwise be discarded, into a beneficial heat source to maintain fuel temperature during low-power conditions. This prevents fuel cooling to dangerous levels while still operating at reduced fuel flow
Solution Approach 2:
The patent recovers waste heat from ancillary systems that would normally be discarded into the environment. This recovered heat is transferred to the fuel or first heat transfer fluid to maintain appropriate temperatures during low-power operation
3Device complexity
If conventional heat sinks are used during sub-idle operation, then system simplicity is maintained, but cooling capacity is insufficient to meet power electronics demands
Solution Approach 1:
The patent creates a universal thermal management architecture where the first heat transfer fluid and heat exchanger serve multiple functions: cooling the gas turbine engine, cooling power electronics, and receiving waste heat from ancillary systems. This multi-functionality increases cooling capacity without proportionally increasing complexity
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 increases the temperature differential for heat transfer, improving efficiency and capacity to dissipate waste heat, preventing fuel temperature rises and component malfunctions, especially during sub-idle operations.
Implementation Method 1
the vapour compression system is configured to increase a temperature of the second heat transfer fluid having passed through the or each second ancillary system to a value greater than a temperature of the first heat transfer fluid entering the second heat exchanger
Implementation Method 2
the first heat exchanger is configured to transfer the waste heat energy from the first heat transfer fluid to a dissipation medium
Implementation Method 3
the chiller is configured to lower a temperature of the first heat transfer fluid prior to the first heat transfer fluid being circulated through the gas turbine engine
Data Source
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AI summary
A thermal management system for an aircraft comprises a first gas turbine engine, a first thermal bus, a first heat exchanger, and a chiller. The first thermal bus comprises a first heat transfer fluid, with the first heat transfer fluid being in fluid communication, in a closed loop flow sequence, between the first gas turbine engine, the first heat exchanger, and the chiller. Waste heat energy generated by the first gas turbine engine, is transferred to the first heat transfer fluid. The chiller is configured to lower a temperature of the first heat transfer fluid prior to the first heat transfer fluid being circulated through the gas turbine engine. The first heat exchanger is configured to transfer the waste heat energy from the first heat transfer fluid to a dissipation medium.