Internal Fluid Reservoir for Gyroscopic Boat Stabilizer Cooling
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Solution Overview
Problem
Existing control moment gyroscopes (CMGs) for boat stabilization face challenges in properly distributing fluid heat transfer medium due to high rotational speeds and thermal expansion/contraction, affecting heat transfer efficiency.
Innovation Solution
A gyroscopic roll stabilizer with a cavity design that includes a first portion for liquid heat transfer medium displacement under centrifugal force and a second portion as a reservoir, optimizing heat transfer by ensuring adequate liquid filling in the gap space between the heat transfer shaft assembly and cavity wall during high-speed operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the flywheel rotates at high speed (5000 rpm or more), then heat transfer efficiency improves due to centrifugal force displacing liquid upward into the first portion, but gas pockets that are present when not rotating displace into the reservoir causing potential cavitation and reduced heat transfer
Solution Approach 1:
The cavity is pre-filled with liquid heat transfer medium before operation. The reservoir portion is designed to accommodate gas pockets that form during high-speed rotation, ensuring continuous liquid contact between the heat transfer shaft assembly and cavity wall for reliable heat transfer throughout operation.
Solution Approach 2:
The system exploits the change in liquid distribution parameters caused by centrifugal force during high-speed rotation. The cavity geometry is optimized to maintain adequate liquid levels in the heat transfer region despite the displacement of liquid upward into the first portion of the cavity at rotational speeds of 5000 rpm or more.
2Temperature
If the cavity is filled completely with liquid heat transfer medium, then heat transfer efficiency is maximized, but thermal expansion of the liquid during operation causes pressure buildup and potential leakage
Solution Approach 1:
The reservoir portion of the cavity is specifically designed to accommodate thermal expansion of the liquid heat transfer medium. This expansion space allows the liquid to expand during operation without causing dangerous pressure buildup or leakage, while still maintaining adequate liquid levels in the heat transfer region.
Solution Approach 2:
The cavity is pre-filled with an optimized amount of liquid that leaves sufficient headspace in the reservoir portion. This preliminary filling strategy ensures both adequate heat transfer contact and accommodation for thermal expansion during operation.
3Temperature
If the cavity geometry is optimized for heat transfer contact, then heat transfer efficiency improves, but the cavity cannot accommodate gas pockets formed during high-speed rotation
Solution Approach 1:
The cavity is segmented into two distinct portions: a first portion that optimizes heat transfer contact between the liquid and heat transfer shaft assembly, and a second portion (reservoir) that accommodates gas pockets during high-speed rotation. This segmentation allows each portion to fulfill its specific function without compromising the other.
Solution Approach 2:
The cavity design utilizes the vertical dimension created by centrifugal force during rotation. The first portion is positioned to maintain liquid contact in the heat transfer region, while the second portion (reservoir) is positioned to receive and contain gas pockets that form upward during high-speed operation, effectively using the radial dimension created by centrifugal effects.
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
Enhances heat transfer efficiency by ensuring optimal filling of the gap space with liquid heat transfer medium, improving cooling of bearings and reducing the risk of failure during high-speed rotation.
Implementation Method 1
A first heat transfer shaft assembly rotationally fixed relative to the flywheel axis extends from the enclosure into the first cavity... liquid heat transfer medium disposed in the first cavity... transfer heat from a flywheel shaft to a heat transfer shaft assembly
Implementation Method 2
liquid heat transfer medium disposed in the first cavity and trapped in the flywheel shaft by the first seal... when the flywheel is rotating at five thousand rpm or more, liquid heat transfer medium in the reservoir is displaced upward into the first portion
Implementation Method 3
When the flywheel is rotating at five thousand rpm or more, liquid heat transfer medium in the reservoir is displaced upward into the first portion (by centrifugal force)
Data Source
AI summary
A gyroscopic roll stabilizer for a boat includes a cavity for liquid heat transfer medium that helps transfer heat from a flywheel shaft to a heat transfer shaft assembly that extends into the cavity. The cavity includes a first portion that overlaps the heat transfer shaft assembly and a reservoir portion that does not, with the second portion acting as a reservoir for the liquid heat transfer medium. The wall of the cavity is shaped such that the first portion is wider than the second portion. When the flywheel is rotating five thousand rpm or more, liquid heat transfer medium in the reservoir is displaced upward into the first portion, and a gas pocket that is present in the first portion when the flywheel is not rotating is displaced into the reservoir, thereby providing better heat transfer when the flywheel is spinning rapidly. Related methods are also disclosed.