Aerospace Electric Propulsion Cooling With Water-Mediated Heat Exchange
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Solution Overview
Problem
Existing aerospace electric propulsion systems require separate cooling systems for electric motors and motor control units, leading to potential fire hazards, excessive tubing, and aerodynamic inefficiencies due to multiple air-cooled heat exchangers.
Innovation Solution
A combined thermal management system using a first fluid cooling circuit for motor control units and a second fluid cooling circuit for electric motors, where the first fluid circuit provides cooling to the second via a heat exchanger, reducing the need for fire detection equipment and optimizing aerodynamics by using water instead of oil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate cooling systems are used for electric motor and motor control units with air-cooled heat exchangers, then each component can be effectively cooled, but the nacelle must be classified as a fire zone due to flammable oil, requiring fire detection and extinguishing equipment
Solution Approach 1:
A water-based intermediate cooling circuit is introduced as a mediator between the air cooling system and the motor control units. The water circuit absorbs heat from the motor control units via a heat exchanger, replacing the need for direct oil cooling and eliminating fire hazards while maintaining effective cooling
Solution Approach 2:
The flammable oil is extracted and removed from the cooling system entirely. Instead of using oil for cooling motor control units, the system uses a water-based circuit that is fire-resistant, thereby eliminating the harmful fire hazard while preserving cooling functionality
2Reliability
If separate cooling systems with two different fluids are used, then each component can be cooled appropriately, but extensive tubing is required connecting multiple heat exchangers
Solution Approach 1:
The cooling systems for the electric motor and motor control units are merged into a unified water-based thermal management system. Both components are cooled by the same water circuit, eliminating the need for separate oil and water circuits and reducing tubing complexity
Solution Approach 2:
The water-based cooling circuit serves multiple functions: it cools both the electric motor and motor control units, and it acts as an intermediate heat transfer medium between the air cooling system and the electronic components. This multi-functionality reduces the overall system complexity
3Reliability
If multiple air-cooled heat exchangers are used for separate cooling systems, then each component can be cooled effectively, but aerodynamic inefficiencies increase due to additional facial area exposed to air flow
Solution Approach 1:
Multiple heat exchangers are merged into a single integrated heat exchanger system. The unified water circuit allows one heat exchanger to serve both the electric motor and motor control units, reducing the total facial area exposed to air flow and minimizing aerodynamic drag
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 reduces weight and space requirements, eliminates the need for fire detection equipment, and improves aerodynamic performance by utilizing water-based cooling, which is more efficient than oil-based cooling.
Implementation Method 1
a first heat exchanger connected to the first fluid cooling circuit for providing cooling to the first fluid cooling circuit; a ram air inlet arranged to provide cooling to the first heat exchanger by ram air cooling
Implementation Method 2
a second heat exchanger, wherein the first fluid cooling circuit is arranged to provide cooling (or heating) to the second fluid cooling circuit via the second heat exchanger
Data Source
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AI summary
The present invention relates to a system (10) for an aircraft (100), wherein the system comprises: an electric motor (12) configured for propulsion of the aircraft; at least one motor control unit (14); a first fluid cooling circuit (16) arranged to circulate a first fluid (18a-c) and comprising at least one first cooling channel (20) in the at least one motor control unit; a first heat exchanger (22) connected to the first fluid cooling circuit for providing cooling to the first fluid cooling circuit; a ram air inlet (24) arranged to provide cooling to the first heat exchanger by ram air cooling; a second fluid cooling circuit (26) arranged to circulate a second fluid (28a-b) and comprising at least one second cooling channel (30) in the electric motor; and a second heat exchanger (32), wherein the first fluid cooling circuit is arranged to provide cooling or heating to the second fluid cooling circuit via the second heat exchanger.