Pumped Two-Phase Cooling Loop for Aircraft Electronics Heat Loads
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Solution Overview
Problem
Aircraft using hydrogen fueled fuel cells face challenges in efficiently cooling the fuel cell stacks and other electronic components, particularly during phases of flight like taxi, takeoff, and climb, where ambient air availability and temperature differences are limited.
Innovation Solution
The implementation of a pumped two-phase cooling system that includes an evaporator, condenser, accumulator, and pump system to efficiently cool heat loads in aircraft, utilizing a liquid that vaporizes in response to cooling, and then condenses back into liquid form for recirculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional air-cooling systems are used for fuel cell stacks during taxi, takeoff, and climb phases, then the system structure is simple, but cooling efficiency is insufficient due to limited ambient air availability and temperature differences
Solution Approach 1:
The patent employs two-phase cooling where the coolant undergoes phase transition from liquid to vapor in the evaporator, absorbing heat from fuel cell stacks. This phase change mechanism provides superior cooling efficiency compared to conventional air-cooling systems, especially during flight phases with limited ambient air availability. The condensed vapor is then returned to the evaporator to repeat the cycle.
Solution Approach 2:
The system utilizes a closed-loop liquid circulation system with pumps, evaporators, condensers, and expansion devices. The hydraulic system circulates liquid coolant through the fuel cell stacks for heat absorption, providing controlled and efficient thermal management during various flight phases.
2Temperature
If thermal management systems are designed with high cooling capacity, then cooling performance is improved, but system size and weight increase
Solution Approach 1:
The two-phase cooling system leverages the latent heat of vaporization to achieve high cooling capacity with compact components. The phase change process allows for efficient heat absorption in a small evaporator volume, reducing the overall system size and weight compared to single-phase liquid cooling systems requiring larger heat exchangers.
Solution Approach 2:
The system utilizes changes in pressure and temperature parameters to control the phase transition of the coolant. By adjusting operating pressures, the boiling point of the coolant is modified to optimize heat absorption at different flight conditions, enabling compact design with adaptive cooling capacity.
3Temperature
If thermal management systems are designed with high cooling capacity, then cooling performance is improved, but system size and weight increase
Solution Approach 1:
The evaporator design utilizes phase transition from liquid to vapor, concentrating heat absorption in a compact volume. This approach achieves high cooling capacity per unit area, reducing the overall footprint of the thermal management system compared to conventional air-cooling or single-phase liquid cooling systems.
Solution Approach 2:
The system integrates multiple components (evaporator, condenser, expansion devices, pumps) into a compact closed-loop configuration. The nested arrangement of heat exchangers and fluid pathways maximizes cooling capacity within minimal spatial envelope, suitable for aircraft space constraints.
4Temperature
If pumped two-phase cooling system is implemented, then cooling efficiency is enhanced and system size is reduced, but system complexity increases
Solution Approach 1:
The system employs phase transition of the coolant as the core cooling mechanism, with liquid evaporating in the evaporator to absorb heat from fuel cell stacks. The phase change provides high cooling efficiency in a compact system, and the condensed vapor is automatically returned to the evaporator through gravity and pressure differential, reducing the need for complex pumping systems.
Solution Approach 2:
The two-phase cooling system utilizes natural convection and gravity to return condensed liquid from the condenser to the evaporator, reducing reliance on complex pumping mechanisms. The phase change process itself drives the circulation, with vapor rising and liquid falling, providing self-regulating flow control that simplifies system design.
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
This solution effectively manages the thermal loads of aircraft components, enhancing cooling efficiency and reducing the size and weight of thermal management systems, while minimizing energy consumption and start-up time for fuel cell stacks.
Implementation Method 1
The evaporator is configured to cool a set of heat loads in an aircraft using a liquid. The liquid forms a vapor in response to cooling the set of heat loads.
Implementation Method 2
The liquid forms a vapor in response to cooling the set of heat loads
Implementation Method 3
The condenser is configured to receive the vapor from the evaporator and cool the vapor in which cooling the vapor forms the liquid.
Implementation Method 4
cooling the vapor forms the liquid
Implementation Method 5
The pump system is configured to pump the liquid stored in the accumulator to the evaporator
Implementation Method 6
The accumulator is configured to receive the liquid from the condenser and store the liquid
Data Source
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AI summary
An aircraft cooling system (4500) comprises an evaporator (4500, 5004), condenser (4512, 4806), an accumulator, and a pump system (4514). The evaporator (4500, 5004) is configured to cool a set of heat loads (4501, 4805, 5011) in an aircraft (199, 400, 3127, 3855, 4502) using a liquid (4516, 5032). The liquid (4516, 5032) forms a vapor (4519, 5031) in response to cooling the set of heat loads (4501, 4805, 5011). The condenser (4512, 4806) is configured to receive the vapor (4519, 5031) from the evaporator (4500, 5004) and cool the vapor (4519, 5031) in which cooling the vapor (4519, 5031) forms the liquid (4516, 5032). The accumulator (4513, 4808, 5008)is configured to receive the liquid (4516, 5032) from the condenser (4512, 4806) and store the liquid (4516, 5032). The pump system (4514) is configured to pump the liquid (4516, 5032) stored in the accumulator (4513, 4808, 5008) to the evaporator (4500, 5004).