Aircraft Thermal Management System Decoupling Power Electronics Cooling from Fuel Flow
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thermal management systems for aircraft gas turbine engines struggle to meet the cooling demands of electrical components during sub-idle engine operation and post-shutdown heat soak back conditions, leading to potential component malfunctions and fuel temperature issues due to insufficient heat dissipation.
Innovation Solution
A thermal management system featuring a closed-loop thermal bus with a heat transfer fluid that directs waste heat from the gas turbine engine and electric machines to a heat exchanger, utilizing two-position valves and optional sink heat exchangers to efficiently transfer heat energy between different dissipation mediums based on temperature differences, ensuring effective heat dissipation even during low-power conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat is transferred to fuel flow during low-power conditions, then cooling demand of power electronics is met, but fuel temperature increases leading to solid fuel deposits formation
Solution Approach 1:
The patent introduces an intermediary thermal management system that decouples the power electronics cooling from direct fuel flow heat transfer. A separate cooling circuit with pump, heat exchanger, and temperature sensors acts as a mediator between the power electronics and fuel system, allowing heat rejection without directly heating the fuel that would form deposits.
Solution Approach 2:
The thermal management system is segmented into separate functional circuits: a fuel system circuit and a power electronics cooling circuit. This segmentation allows independent control of each system - the fuel system can maintain its temperature to prevent deposits while the power electronics cooling circuit actively removes heat from electrical components.
2Reliability
If conventional heat sinks are used during sub-idle conditions, then cooling is provided during above-idle operation, but heat sinks become unavailable or insufficient during sub-idle and post-shutdown conditions
Solution Approach 1:
The thermal management system is designed with multi-functionality to handle diverse operating conditions. The same cooling circuit serves both above-idle and sub-idle conditions, while the system can alternatively reject heat to engine oil or ambient air depending on the operational phase, making the heat rejection capability universal across all engine states.
Solution Approach 2:
The system dynamically adapts its heat rejection strategy based on real-time operating conditions. Pumps, valves, and heat exchangers are controlled to redirect heat flow between different sinks (fuel, engine oil, ambient air) according to the current engine state, ensuring continuous adaptability from sub-idle through shutdown conditions.
3Loss of energy
If fuel flow rate is reduced during low-power conditions, then fuel consumption is optimized, but heat transfer capability decreases causing high fuel temperature
Solution Approach 1:
The patent extracts the heat rejection function from the fuel flow itself. Instead of relying on fuel flow to carry away heat from power electronics, a separate dedicated cooling circuit is established that independently removes heat from power electronics without depending on fuel flow rate, thus decoupling cooling capability from fuel consumption.
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 provides reliable and efficient heat dissipation across various aircraft operational phases, preventing component malfunctions and fuel temperature issues by optimizing heat transfer and dissipation strategies, thus enhancing the performance and reliability of power electronics and engine systems.
Implementation Method 1
waste heat energy generated by at least one of the first gas turbine engine, and the or each first electric machine, is transferred to the first heat transfer fluid
Implementation Method 2
a quantity Q FIRST_IN of heat energy is transferred from a first dissipation medium to the first heat transfer fluid
Implementation Method 3
the first heat exchanger module comprises a first flow path and a second flow path, the first flow path being configured to direct a flow of the heat transfer fluid to a first heat dissipation portion in which a quantity Q FIRST_IN of heat energy is transferred from a first dissipation medium to the first heat transfer fluid
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A thermal management system for an aircraft comprises a first gas turbine engine, one or more first electric machines rotatably coupled to the first gas turbine engine, a first thermal bus, and a first heat exchanger module. 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 or each first electric machine, and the first heat exchanger. Waste heat energy generated by at least one of the first gas turbine engine, and the or each first electric machine, is transferred to the first heat transfer fluid. The first heat exchanger module comprises a first flow path and a second flow path. The first flow path is configured to direct a flow of the heat transfer fluid to a first heat dissipation portion in which a quantity QFIRST_IN of heat energy is transferred from a first dissipation medium to the first heat transfer fluid, and subsequently to a second heat dissipation portion in which a quantity QSECOND_OUT of heat energy is transferred from the heat transfer fluid to a second dissipation medium, in dependence on a temperature of the first heat transfer fluid entering the first heat exchanger module, a temperature of the first heat dissipation medium, and a temperature of the second heat dissipation medium.