Loop Heat Pipe Remote Compensation Chamber Design
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Solution Overview
Problem
Current capillary driven two-phase thermal control systems for spacecraft face limitations in expandability, controllability, and vapour parasitic heat leak tolerance, particularly in multi-evaporator designs, leading to unreliable operation under varying thermal conditions.
Innovation Solution
A two-phase capillary driven LHP system with a remote compensation chamber and secondary capillary pump, allowing for flexible configuration with multiple evaporators and condensers, vapour parasitic heat leak tolerance, and scalable design, where the remote compensation chamber manages vapour and liquid phases to prevent dry-out and non-condensable gas accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple evaporators with individual compensation chambers are used, then the number of evaporators increases and thermal control flexibility improves, but the compensation chamber volume increases rapidly and device complexity increases
Solution Approach 1:
The patent merges multiple individual compensation chambers into a single shared compensation chamber that serves multiple evaporators. This consolidation reduces the total volume required while maintaining the ability to support multiple evaporators operating at different temperatures and heat loads, directly resolving the contradiction between increasing evaporator count and minimizing compensation chamber volume.
Solution Approach 2:
The shared compensation chamber is designed to perform multiple functions simultaneously: it serves as the compensation chamber for all evaporators, acts as a liquid reservoir, and provides thermal coupling between evaporators. This multi-functionality allows a single chamber to replace multiple individual chambers, reducing overall system volume while maintaining adaptability.
2Adaptability or versatility
If multiple evaporators with individual compensation chambers are used, then thermal control flexibility improves, but device complexity and mass increase
Solution Approach 1:
The patent combines multiple compensation chambers into one shared chamber, reducing the number of components and interconnections required. This merging simplifies the overall system architecture while preserving thermal control flexibility through the chamber's ability to serve multiple evaporators simultaneously at different operating conditions.
Solution Approach 2:
The shared compensation chamber performs multiple functions including liquid compensation, thermal coupling, and vapor-liquid separation for all evaporators. This multi-functionality reduces the need for separate dedicated components for each evaporator, thereby reducing device complexity while maintaining adaptability.
3Stability of the object's composition
If evaporators are rigidly connected at close distances, then structural stability improves, but scalability and flexibility in component locations deteriorate
Solution Approach 1:
The shared compensation chamber acts as an intermediary component that couples multiple evaporators without requiring rigid direct connections between them. This intermediary approach allows evaporators to be positioned at greater distances and in more flexible configurations while maintaining system stability through the common compensation chamber that mediates thermal and fluid interactions.
4Device complexity
If vapour parasitic heat leak is not addressed, then device complexity remains low, but reliability deteriorates due to dry-out and non-condensable gas accumulation
Solution Approach 1:
The patent extracts and removes vapour from the system by providing dedicated vapour removal pathways from the shared compensation chamber. This extraction of harmful vapour prevents parasitic heat leak, dry-out conditions, and non-condensable gas accumulation, thereby improving reliability without requiring complex additional systems.
Solution Approach 2:
The patent converts the potentially harmful vapour parasitic heat leak into a manageable phenomenon by designing the shared compensation chamber to actively manage and remove vapour. The vapour generation is anticipated and addressed through deliberate vapour removal mechanisms, transforming a reliability threat into a controlled aspect of system 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
The system achieves reliable operation across a wide range of conditions, enabling flexible configuration, vapour parasitic heat leak tolerance, and efficient heat load sharing, with the ability to handle varying power inputs and temperatures, and supports a large number of evaporators and condensers without the need for large compensation chambers.
Implementation Method 1
The primary capillary pump serves for absorbing heat from the equipment, which has to be cooled, and for providing fluid heat continuous circulation between the evaporator and the condenser
Implementation Method 2
The secondary capillary pump serves for supplying liquid to the primary wick and, together with the stabilization-compensation chamber and the remote compensation chamber, for providing fluid/heat intermittent circulation in transient regimes of operation of the system
Implementation Method 3
In steady state regimes of operation of the system, the stabilization-compensation chamber serves to remove internal heat leak through a primary capillary pump by convection and condensation on the heat exchanger surface
Data Source
Figure 1a
Figure 1b
Figure 1c
AI summary
Loop heat pipe apparatus (1) for heat transfer and thermal control, using a two-phase fluid as a working media and comprising: - at least one evaporator (2) to be connected with a heat source and comprising a thermal stabilization-compensation chamber (10) attached to the at least one evaporator (2) and a secondary capillary pump (40) located inside the thermal stabilization-compensation chamber (10), - at least one condenser (27) to be connected with a heat sink, - liquid lines (24) and vapour lines (28) connecting the at least one evaporator (2) and the at least one condenser (27), and - a remote compensation chamber (20), wherein the thermal stabilization-compensation chamber (10) comprises a two-phase reservoir (5) and a liquid accumulator reservoir (6) separated by a heat exchange surface (15), such that the remote compensation chamber (20) is hydraulically connected with the two-phase reservoir (5) and the liquid accumulator reservoir (6).