Air Cycle Cooling for Hybrid-Electric Propulsion Motors
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Solution Overview
Problem
Efficient cooling of electrical components in turbo electric airplane propulsion systems, particularly those located near thermal engines, is challenging due to difficult location constraints.
Innovation Solution
An integrated air cooling system utilizing air cycle machine cooling, which includes a compressed air source directing air to a heat exchanger and then to an electric turbine, with expanded air used to cool the electric motor or generator, and optionally passing through a water separator and hollow wires, while also providing air supply for cabin or cargo cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If electric motors or generators are located next to thermal engines for space optimization, then the propulsion system layout is improved, but cooling efficiency deteriorates due to difficult location constraints
Solution Approach 1:
The air cooling system divides the thermal management function into separate components: a heat exchanger for heat rejection, an expansion turbine for cooling and power generation, and distribution channels for delivering cooled air to the electric motor or generator. This segmentation allows each component to be optimized independently while maintaining effective cooling despite the constrained location near thermal engines.
2Temperature
If air cooling system components are added to cool electric motors near thermal engines, then cooling efficiency is improved, but system weight increases
Solution Approach 1:
The expansion turbine serves multiple functions: it cools the compressed air through adiabatic expansion, generates rotational power that can drive the compression process or contribute to propulsion, and reduces the overall power requirement for the cooling system. This multi-functionality minimizes the need for separate heavy components while achieving effective cooling.
Solution Approach 2:
The system utilizes parameter changes in the air throughout the cycle: compression increases temperature and pressure, heat exchanger rejection lowers temperature at constant pressure, and expansion turbine cooling further reduces temperature and pressure. These parameter changes enable efficient heat transfer and cooling without requiring excessive mass in the cooling components.
3Device complexity
If compressed air is used for both thermal combustor and electric motor cooling, then system complexity is reduced, but air supply pressure requirements increase
Solution Approach 1:
The system dynamically adjusts air flow distribution between the thermal combustor and the electric motor cooling system based on operational requirements. The expansion turbine and controllable valves enable flexible regulation of pressure and flow rates, allowing the single compressed air source to meet varying demands without requiring excessively high pressure ratings throughout the 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 efficient cooling of electric motors and generators with reduced weight and improved reliability, while optimizing magneto-electric properties and power-to-weight ratio.
Implementation Method 1
a heat exchanger, and the portion of air directed to the heat exchanger is cooled via outside or ambient air flow
Implementation Method 2
a portion of expanded air is configured to be directed from the electric turbine to the electric motor for cooling of the electric motor
Implementation Method 3
the portion of expanded air is configured to be directed to a water separator prior to being directed to the electric motor or generator for cooling of the electric motor or generator
Implementation Method 4
a compressed air source for a thermal combustor
Data Source
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AI summary
The present disclosure provides air cooling systems and methods for propulsion systems (e.g., aviation or aerospace propulsion systems). More particularly, the present disclosure provides integrated air cooling systems and methods utilizing air cycle machine cooling for hybrid-electric aircraft or aerospace propulsion systems or the like. The present disclosure provides integrated air cycle machine cooling into the hybrid propulsion system (e.g., into the wing-mounted hybrid propulsion system). As such, the air cooling systems and methods of the present disclosure can minimize weight while improving electric motor/generator cooling.