Shape-Memory Alloy Thermal Actuator for Compact Heat Transfer
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Solution Overview
Problem
Existing thermal actuators, such as those using paraffin and shape-memory alloys, face challenges in size reduction, weight minimization, and effective heat transfer due to the need for containers and interposed materials that limit contact area and heat transfer efficiency.
Innovation Solution
A thermal actuator unit featuring a shape-memory alloy thermal deformation part with columnar bodies and a strut system that allows for wide-area contact between a support plate and a movable plate, utilizing a disk spring and thermally conductive materials to enhance heat transfer and reduce size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If paraffin is used as the thermal actuator material, then the thermal actuator can be operated in accordance with a change in thermal environment, but the size and mass are increased due to the need for a container
Solution Approach 1:
The invention extracts and eliminates the container from the thermal actuator system by using a shape-memory alloy that can change its own shape without being enclosed. The shape-memory alloy directly undergoes phase transformation to achieve the thermal actuation function, removing the unnecessary container component and its associated weight.
Solution Approach 2:
The invention utilizes the parameter change of the shape-memory alloy's crystal structure during phase transformation. The alloy changes from a high-temperature phase to a low-temperature phase, causing significant shape change that drives the thermal actuator operation without requiring a container to hold phase-changing material.
2Adaptability or versatility
If a shape-memory alloy is interposed between a heating element and a heat exchanger, then the thermal actuator can switch between contact and non-contact states, but the contact area is reduced and heat transfer efficiency deteriorates
Solution Approach 1:
The invention extracts and removes the shape-memory alloy from the heat transfer path between the heating element and heat exchanger. The shape-memory alloy is positioned only where needed for actuation, allowing direct contact between the heating element and heat exchanger surfaces when contact is required, thus eliminating the thermal resistance introduced by an interposed alloy layer.
Solution Approach 2:
The invention uses a thin film or interface structure as an intermediary that allows both mechanical actuation and efficient heat transfer. This intermediary enables the shape-memory alloy to provide contact switching functionality while maintaining thermal conductivity, or allows direct metal-to-metal contact when full heat transfer efficiency is needed.
3Adaptability or versatility
If a shape-memory alloy is interposed between a heating element and a heat exchanger, then the thermal actuator can switch between contact and non-contact states, but the contact area is limited
Solution Approach 1:
The invention extracts the shape-memory alloy from the contact interface area and positions it only where actuation force is needed. This allows the heating element and heat exchanger to have maximum possible contact area when in contact state, as the alloy is not occupying space in the heat transfer path.
Solution Approach 2:
The invention segments the shape-memory alloy into specific actuation zones separate from the heat transfer zones. The alloy is positioned in discrete locations to provide the necessary actuation force while leaving the majority of the heating element and heat exchanger surfaces available for maximum contact area and efficient heat transfer.
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 enables a compact, lightweight thermal actuator that can efficiently switch between contact and non-contact states, reducing power consumption and maintaining stable temperature control, suitable for applications like spacecraft thermal management.
Implementation Method 1
a thermal deformation part which is disposed on a side of the first member opposite to a side with the second member and has a shape-memory alloy to be deformed to the side with the second member due to heat
Implementation Method 2
an elastic part which is disposed between the first member and the second member
Data Source
AI summary
A thermal actuator unit of the present invention includes a first member, a second member, an elastic part which is disposed between the first member and the second member, and a thermal deformation part which is disposed on a side of the first member opposite to a side with the second member and has a shape-memory alloy to be deformed to the side with the second member due to heat.