Rotating Heat Pipe Gearbox Cooling for Aircraft Drivetrain
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Solution Overview
Problem
Aircraft drivetrains face challenges in managing heat transfer, particularly during emergency conditions when primary lubrication systems fail, leading to excessive heat and potential component failure, as existing heat pipes are inefficient in dynamic environments due to gravitational and centrifugal forces.
Innovation Solution
The implementation of uniquely designed heat pipes within the drivetrain, including a mandrel assembly with misaligned channels to facilitate the movement of the working fluid despite centrifugal forces, and supplemental heat exchangers to enhance heat transfer, allowing for continuous heat removal during 'run dry' conditions without active command.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional heat pipes are used in aircraft drivetrains, then heat transfer capability is improved, but performance deteriorates under dynamic conditions due to gravitational and centrifugal forces
Solution Approach 1:
The patent applies the dynamics principle by making the heat pipe rotatable within the hollow shaft, allowing it to orient itself dynamically in response to centrifugal forces. The heat pipe can rotate to maintain optimal positioning where the evaporator section remains in contact with the heat-generating component while the condenser section positions itself in the lubricant flow path, thereby maintaining reliable heat transfer performance under varying dynamic flight conditions
Solution Approach 2:
The patent applies parameter changes by modifying the physical state and positioning of the heat pipe components. The heat pipe transitions from a static configuration to a dynamic one where its angular position changes based on operational conditions. This allows the heat pipe to adapt its geometry and orientation parameters to overcome gravitational and centrifugal forces that would otherwise hinder heat transfer effectiveness
2Duration of action of moving object
If lubricant reserves are increased to maintain operation during primary lubrication system failure, then operational duration is improved, but aircraft weight increases
Solution Approach 1:
The patent applies the extraction principle by removing the heat extraction function from the lubrication system and placing it into a separate, dedicated heat pipe system. This allows the lubrication system to use minimal lubricant reserves solely for lubrication purposes while the heat pipe independently handles heat removal, thereby extending operational duration during emergencies without requiring increased lubricant quantities or additional weight
Solution Approach 2:
The patent applies the intermediary principle by introducing the heat pipe as a mediating device between the heat-generating drivetrain components and the lubricant. The heat pipe acts as an intermediate heat transfer medium that extracts heat from the drivetrain components directly, reducing the thermal load on the lubrication system and allowing it to function effectively with reduced lubricant reserves
3Reliability
If secondary lubrication systems are used to provide lubrication during primary system failure, then operational reliability is improved, but heat removal capability deteriorates
Solution Approach 1:
The patent applies the segmentation principle by dividing the emergency protection system into two separate functional components: a secondary lubrication system for providing lubrication and a heat pipe system for heat removal. This segmentation allows each system to be optimized for its specific function - the lubrication system ensures component lubrication while the heat pipe maintains thermal management capability, thereby achieving both reliability and heat removal performance during primary system failure
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 enables continuous heat removal from aircraft drivetrains during lubrication system failures, extending operational time and reducing the risk of component failure, while also reducing the weight and reserve requirements of lubricants by integrating heat pipes into hollow shafts and gears.
Implementation Method 1
Heat pipes are a device commonly used to transfer heat. Heat pipes are a transfer mechanism that can transport large quantities of heat with a very small difference in temperature between hot and cold interfaces.
Implementation Method 2
Heat pipes are a transfer mechanism that can transport large quantities of heat with a very small difference in temperature between hot and cold interfaces.
Implementation Method 3
External forces, such as gravitational and centrifugal forces, can hinder performance of the heat pipe.
Implementation Method 4
External forces, such as gravitational and centrifugal forces, can hinder performance of the heat pipe.
Data Source
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AI summary
A cooling system using one or more heat pipes (54;70) rotating about a central axis (53) to transfer heat energy from one medium to another. The heat pipes are oriented within a rotating member (33) such that the axis (55) of the heat pipe is non-coaxial with that of a central axis (53) of the rotating member. Centrifugal forces are used to assist the movement of the working fluid within the heat pipe. The cooling system also includes heat pipes (70;80) associated with a planetary carrier assembly (27) and supplemental heat exchangers (100) for use in aircraft and other machinery.