Advanced Control Two-Phase Heat Transfer Loop for Spacecraft Thermal Management
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Solution Overview
Problem
Current multi-evaporator two-phase heat transfer loops for spacecraft thermal control face limitations in expandability, controllability, and vapor parasitic heat leak tolerance, leading to unreliable performance under varying thermal conditions.
Innovation Solution
A two-phase mechanically or capillary driven advanced control heat transfer loop (ACHTL) with a remote compensation chamber and advanced temperature control, featuring a primary capillary pump, secondary capillary pump, and a controller to manage vapor parasitic heat leaks, allowing for flexible evaporator and condenser configurations and scalable design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple evaporators are added to increase thermal control coverage, then the thermal control capability is improved, but the system complexity and difficulty of controlling temperature distribution increase
Solution Approach 1:
The patent merges multiple evaporators into a common evaporator assembly that shares a single compensation chamber and capillary pump structure. This integration allows multiple heat sources to be cooled simultaneously while reducing the number of independent components, thereby improving thermal control coverage without proportionally increasing system complexity.
Solution Approach 2:
The compensation chamber and capillary pump serve multiple functions: they compensate for volume changes in all evaporators simultaneously, distribute working fluid to multiple heat sources, and maintain pressure equilibrium across the entire system. This multi-functionality reduces the need for separate control mechanisms for each evaporator.
2Productivity
If a capillary pump structure is used to improve heat transfer efficiency, then the heat transfer performance is improved, but vapor parasitic heat leaks increase leading to unreliable operation
Solution Approach 1:
The patent applies different structural characteristics to different regions of the capillary pump: the outer peripheral region has a structure that promotes liquid flow and heat transfer efficiency, while the inner region is designed to prevent vapor penetration and parasitic heat leaks. This localized differentiation allows the system to achieve high heat transfer performance without sacrificing reliability.
Solution Approach 2:
The patent converts the potential harm of vapor parasitic heat leaks into a beneficial design feature by incorporating a vapor barrier structure that specifically targets and blocks vapor penetration paths. The barrier utilizes the natural tendency of vapor to follow specific flow paths and redirects or blocks it, transforming a reliability issue into an opportunity for enhanced vapor management.
3Stability of the object's composition
If the compensation chamber volume is increased to accommodate thermal expansion, then the thermal stability is improved, but the device volume and mass increase
Solution Approach 1:
The patent segments the compensation function by integrating the compensation chamber directly within the evaporator assembly rather than as a separate large-volume component. The compensation chamber is distributed across multiple evaporator units, each with its own integrated compensation capability, reducing the need for a single large compensation volume while maintaining thermal stability.
Solution Approach 2:
The compensation chamber is nested within the evaporator structure, utilizing the existing evaporator volume and housing. This nested arrangement allows the compensation chamber to occupy space that would otherwise be unused or structural, thereby providing thermal compensation capability without increasing the overall external dimensions of the thermal control system.
4Device complexity
If a single large compensation chamber is used to simplify the structure, then the structural simplicity is improved, but the controllability and temperature distribution uniformity worsen
Solution Approach 1:
The patent divides the compensation function across multiple distributed compensation chambers, each associated with a specific evaporator or group of evaporators. This segmentation allows for localized temperature control and compensation, enabling precise control of temperature distribution across different heat sources while maintaining relatively simple individual chamber structures.
Solution Approach 2:
The patent incorporates dynamic control elements within each compensation chamber, such as adjustable capillary structures or controllable fluid pathways, that allow the system to adapt compensation rates and temperature control parameters based on real-time thermal conditions. This dynamic capability enables precise temperature control without requiring overly complex static structures.
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 ACHTL system ensures reliable operation with minimal parasitic heat leak, enabling flexible and scalable thermal management across a wide range of conditions, including multiple evaporators and varying heat loads, while maintaining efficient heat transfer and temperature control.
Implementation Method 1
a primary capillary pump, which serves to provide continuous circulation of working fluid between the evaporator and the condenser
Implementation Method 2
Heat applied to the evaporator from electronic equipment is used for phase transformation of working fluid from liquid to vapor
Implementation Method 3
two phases of this heat carrier, vapor and liquid, are always present in the circuit
Implementation Method 4
The heat accumulated in the vapor phase is dissipated in the condenser by condensation
Implementation Method 5
at least one heating element installed on the remote compensation chamber
Data Source
AI summary
The advanced control heat transfer loop apparatus (1) for heat transfer and thermal control applications uses a two-phase fluid as a working media and comprises at least one evaporator (2) to be connected with a heat source and comprising primary capillary pump (4), a thermal stabilization-compensation chamber (3) being attached to the at least one evaporator (2), at least one condenser (24) to be connected with a heat sink, liquid lines (22) and vapor lines (23) connecting the at least one evaporator (2) and the at least one condenser (24), a remote compensation chamber (20), temperature sensors (27) for detecting the temperature of the remote compensation chamber (20) and at the thermal stabilization compensation chamber (3) attached to the at least one evaporator (2), at least one heating element (19) for heating the remote compensation chamber (20), and a controller (28). The controller (28) is configured to monitor the temperatures detected by the sensors (27) and to control the heating element (19) in such a way that the value of the difference ΔTControl between the temperature of the remote compensation chamber (20) and the temperature of the thermal stabilization-compensation chamber (3) attached to the at least one evaporator (2) is positive.