Ram Air Fan Cooling System With Mechanical Pump Coupling
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Solution Overview
Problem
Conventional power electronics cooling systems in aircraft rely on ram air flow, but they face challenges in efficiently distributing cooling liquids to remote components, particularly when the aircraft is on the ground, as pumps are often located far from the ram air fan, leading to inefficiencies in cooling and energy transfer.
Innovation Solution
A power electronics cooling system that integrates a ram air fan with a first and second cooling pump, where the ram air fan motor is mechanically coupled to the pumps, allowing rotation transfer during flight and electrical power during ground operations, ensuring efficient cooling liquid circulation to electronics packages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pumps are located at positions remote from the ram air fan (e.g., in wheel wells), then the cooling system can serve distributed components, but the efficiency of cooling and energy transfer deteriorates
Solution Approach 1:
The system divides the cooling function into two segments: a first pump near the ram air fan for efficient cooling liquid circulation, and a second pump at remote locations for targeted cooling delivery. This segmentation maintains cooling efficiency by keeping the primary pump close to the air source while still enabling distributed cooling through the second remote pump.
Solution Approach 2:
The first pump acts as an intermediary between the ram air fan and the remote second pump. It receives mechanical energy directly from the fan and transfers it to the cooling liquid, then delivers this pre-cooled liquid to remote components via the second pump, thereby maintaining overall system efficiency despite the remote distribution architecture.
2Loss of energy
If the ram air fan is mechanically coupled to cooling pumps, then energy transfer efficiency improves during flight, but the system complexity increases
Solution Approach 1:
The ram air fan is designed with multi-functionality: it serves both as a cooling air source and as a mechanical energy source to drive the cooling pumps through direct mechanical coupling. This universal design improves energy transfer efficiency by eliminating separate power sources while the modular pump architecture manages the added complexity.
Solution Approach 2:
The mechanical coupling between the ram air fan and pumps is designed to be dynamically adaptive, allowing the system to optimize energy transfer during flight while maintaining operational flexibility. The coupling mechanism can accommodate varying operational conditions and maintain efficiency across different flight regimes.
3Adaptability or versatility
If electrical power is provided to the ram air fan motor controller on the ground, then the fan can operate independently, but the mechanical coupling to pumps is not utilized
Solution Approach 1:
The system dynamically switches between two operational modes: on the ground, the ram air fan motor controller provides electrical power for independent fan operation; during flight, the mechanical coupling is utilized to transfer kinetic energy directly to the pumps. This dynamic adaptability ensures operational flexibility while maximizing energy utilization efficiency in each regime.
Solution Approach 2:
The system alternates between electrical power mode (ground operations) and mechanical energy transfer mode (flight operations) based on aircraft state. This periodic switching between power sources optimizes the use of available energy resources while maintaining operational flexibility across different phases of aircraft operation.
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 configuration ensures effective cooling of electronics components by utilizing ram air flow for both cooling and energy generation, maintaining component temperatures within safe limits during flight and ground operations, thereby preventing overheating and damage.
Implementation Method 1
Air drawn from the outside environment by a ram air fan may be passed across a heat exchanger to provide cooling to various cooling liquids
Implementation Method 2
the output shaft of the ram air fan provides rotation to the first pump motor while the aircraft is in flight
Data Source
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AI summary
A power electronics cooling system (100) includes a ram air fan (102) with one or more blades (252) and a ram air fan motor (130) connected via an output shaft (120). The ram air fan (102) draws in air and passes it across a heat exchanger (112) to cool one or more cooling liquids (108,118). One or more pumps (104,114) pressurize and pump the cooling liquids (108,118) to various electronic components, including one or more motor controllers (136,178). The pumps (104,114) may be mechanically or electrically coupled to the output shaft (120) of the ram air fan (102), such that the motor of the ram air fan (130) provides energy to the pumps.