Conduction-Cooled Gimbaled IMU Thermal Management
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Solution Overview
Problem
Inertial measurement units in navigation systems are temperature sensitive and require effective temperature control, with existing cooling methods like internal fans and bellyband cooling tubes being inefficient and prone to unpredictable heat transfer.
Innovation Solution
A conduction-cooled gimbaled inertial measurement unit with an isothermal dome and thermal shells that facilitate heat transfer through a gimbal assembly, using a hermetic enclosure with a thermally conductive gas and external cooling tubes to maintain a constant temperature, reducing convection and enhancing predictive heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If internal fan with flow diffusers is used to cool the inertial measurement unit, then cooling capability is provided, but heat transfer becomes unpredictable and system complexity increases
Solution Approach 1:
The patent replaces the mechanical fan-based convection cooling system with a conduction-based thermal management system. Thermal shells are attached directly to heat-generating components and conduct heat to cooling tubes, eliminating the unpredictable convection currents and mechanical moving parts while providing reliable, predictable heat transfer paths.
Solution Approach 2:
The patent introduces thermal shells as intermediary components between heat-generating components and cooling tubes. These thermal shells serve as heat transfer mediators, conducting heat from the inertial measurement unit components through defined thermal paths to the cooling tubes, thereby enabling predictable and controllable temperature management.
2Temperature
If internal bellyband cooling tubes are used to cool the inertial measurement unit, then cooling is provided, but heat transfer efficiency is insufficient and temperature control is poor
Solution Approach 1:
The patent applies thermal shells selectively to specific heat-generating components within the inertial measurement unit, creating localized thermal management zones. Each thermal shell is positioned to contact specific components that require cooling, providing targeted temperature control rather than uniform cooling throughout the entire unit, thereby achieving better temperature uniformity in critical areas.
Solution Approach 2:
The patent divides the thermal management system into discrete thermal shells, each associated with specific heat-generating components. This segmentation allows independent optimization of cooling for different components, enabling precise temperature control for each segment while maintaining overall system temperature uniformity.
3Temperature
If convection-based cooling is used, then cooling capability is achieved, but heat transfer predictability decreases and navigation accuracy is compromised
Solution Approach 1:
The patent replaces convection-based cooling with conduction-based cooling throughout the thermal management system. Thermal shells conduct heat directly to cooling tubes through solid thermal paths, eliminating the unpredictable nature of convection currents. This provides stable, predictable heat transfer that ensures consistent temperature control and maintains navigation measurement precision.
4Temperature
If multiple cooling components are added to improve temperature control, then temperature stability improves, but device complexity increases
Solution Approach 1:
The patent merges the thermal management function into the existing gimbal structure by integrating thermal shells with the gimbal components. The thermal shells are attached to gimbal parts that already exist in the system, combining structural and thermal management functions into a single integrated design, thereby improving temperature stability without proportionally increasing device complexity.
Solution Approach 2:
The gimbal components serve dual functions: mechanical support/rotation and thermal conduction. The thermal shells attached to gimbal components use the same structural elements for both mechanical and thermal purposes, reducing the need for separate dedicated cooling components and thereby limiting the increase in device complexity while achieving improved temperature stability.
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 solution ensures a stable and accurate temperature control for inertial measurement units, improving navigation accuracy by minimizing temperature fluctuations and eliminating the need for additional navigation instruments.
Implementation Method 1
each of the gimbals having a respective thermal shell to conduct heat from the inertial measurement unit to the isothermal dome
Implementation Method 2
the isothermal dome having a cooling tube disposed on an external surface of the isothermal dome to transfer heat from the plurality of gimbals and maintain the isothermal dome at a constant temperature
Implementation Method 3
using a hermetic enclosure with a thermally conductive gas and external cooling tubes to maintain a constant temperature, reducing convection and enhancing predictive heat transfer
Data Source
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AI summary
Conductive cooled gimbaled inertial measurement units are disclosed herein. An example apparatus includes an inertial measurement unit, a gimbal assembly in which the inertial measurement unit is disposed, the gimbal assembly having gaps between each gimbal of the gimbal assembly, the gaps including a gas to conduct heat from the gimbal assembly, and an isothermal dome at least partially surrounding the gimbal assembly, the isothermal dome having a cooling tube disposed on an external surface of the isothermal dome to transfer heat from the gimbal assembly via conduction.