Capillary Pump Assisted Heat Pipe for Cold Environment Thawing
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Solution Overview
Problem
Standard heat pipes become nonfunctional in cold environments due to freezing of the working fluid, leading to inadequate heat rejection when heat loads resume, causing electronic components to overheat.
Innovation Solution
A heat transport device with a capillary container, wick, and working fluid, featuring a capillary pump and reservoir to supply additional working fluid when frozen, allowing operation in both normal and thaw modes to maintain heat transfer efficiency across varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard heat pipe is used in cold environments, then the heat pipe structure is simple and reliable, but the working fluid freezes in the condenser section causing the heat pipe to become nonfunctional
Solution Approach 1:
The heat transport device is divided into two functional sections: a heat pipe section for normal heat transport and a capillary pump section for fluid replenishment. The capillary pump includes a reservoir separated from the heat pipe, allowing independent fluid management. This segmentation enables the system to address freezing issues without compromising the simplicity of the standard heat pipe operation.
Solution Approach 2:
The capillary pump and reservoir are pre-configured with additional working fluid before deployment. When freezing occurs, the system automatically activates the capillary pump to deliver pre-stored fluid to the heat pipe, eliminating the need for external intervention or complex thawing procedures.
2Device complexity
If the heat pipe operates in freezing conditions, then the device structure remains simple, but the working fluid becomes depleted from the evaporator rendering the heat pipe nonfunctional
Solution Approach 1:
The capillary pump acts as an intermediary component between the reservoir and the heat pipe. It automatically detects fluid depletion conditions and transfers working fluid from the reservoir to the heat pipe, maintaining continuous operation without requiring complex control systems or external power sources.
Solution Approach 2:
The system employs self-regulating capillary wicks that automatically control fluid flow based on temperature and pressure conditions. The capillary pump activates only when needed, drawing fluid from the reservoir to replenish the heat pipe, thereby maintaining reliability through autonomous operation rather than external control mechanisms.
3Reliability
If a capillary pump with reservoir is added to supply additional working fluid, then the heat rejection capability is maintained in cold environments, but the device complexity increases
Solution Approach 1:
The capillary pump utilizes capillary action through porous wick material to transfer working fluid from the reservoir to the heat pipe without requiring mechanical moving parts, motors, or external power sources. This hydraulic approach maintains reliability while minimizing the addition of complex mechanical components.
Solution Approach 2:
The capillary pump employs porous wick material that leverages capillary forces to automatically control fluid flow based on temperature and pressure differentials. This passive fluid control mechanism enables the system to maintain heat rejection capability without complex active control systems, sensors, or power consumption.
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
Enables continuous heat rejection by thawing the frozen working fluid without significant power consumption, ensuring reliable temperature control for electronic components across different environmental conditions.
Implementation Method 1
Heat applied to the evaporator section by an external source is conducted through the pipe wall and wick structure where it vaporizes the working fluid
Implementation Method 2
the vapor condenses, releasing its latent heat of vaporization to the provided heat sink through conduction, convection, or radiation
Implementation Method 3
the capillary pressure created by menisci in the wick pumps the liquid phase working fluid back to the evaporator section
Data Source
AI summary
A heat transport device includes a heat pipe having a capillary container having a wick and a working fluid arranged therein. A first heat source is coupled to a first end of the capillary container to define an evaporator section and a cold sink is coupled to a second end of the capillary container to define a condenser section. A capillary pump includes an evaporator and a reservoir configured to store an additional supply of working fluid. A second heat source coupled to the evaporator is configured to vaporize the working fluid arranged therein. A fluid loop couples the capillary pump to the heat pipe. Upon detection of a predetermined condition indicative that a majority of the working fluid within the heat pipe is frozen, the capillary pump is configured to supply vaporized working fluid to the heat pipe.