Demonstration of a shape memory alloy torque tube-based morphing radiator
Demonstration of a shape memory alloy torque tube-based morphing radiator
复制标题
基于形状记忆合金扭矩管的变形散热器的演示
DOI：
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
D. Hartl
中科院分区：
文献类型：
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作者：
Jorge B. Chong;P. Walgren;D. Hartl
长距离载人太空探索将需要先进的热控制系统（TCS），能够处理各种热负荷。TCS适应热环境的能力通过调节比来描述。开发高负荷比的散热器是提高TCS技术的关键。本文介绍了一种新型的变形散热器设计，以实现高的调节比，通过改变自己的辐射角因子和有效发射率，通过使用形状记忆合金（SMA）。这种散热器具有两个SMA扭矩管悬臂刚性夹具。工作流体在SMA管内通过环形流动系统输送。在寒冷的环境中，固定到管的自由端的散热器面板以平行板的方式垂直定向，其中高发射率的内面具有对环境的受限视野，并且散热被最小化。当系统加热时，管通过在相反方向上扭转而致动，使面板处于水平位置，内表面暴露以最大化散热。当系统冷却下来时，管反向扭转，使面板恢复到垂直方向，其中热排放再次最小化。这种可变排热系统具有实现比当前最先进系统更高的调节比的潜力。一个台式原型已被设计和测试，以证明驱动和探索内部热传递的影响。本文描述了原型设计、测试和结果。
Long-distance crewed space exploration will require advanced thermal control systems (TCS) with the ability to handle a wide range of thermal loads. The ability of a TCS to adapt to the thermal environment is described by the turndown ratio. Developing radiators with high turndown ratios is critical for improving TCS technology. This paper describes a novel morphing radiator designed to achieve a high turndown ratio by varying its own radiative view factor and effective emissivity through the use of shape memory alloys (SMAs). This radiator features two SMA torque tubes cantilevered to a rigid fixture. The working fluid is transported within the SMA tubes through an annular flow system. In a cold environment, radiator panels fixed to the free ends of the tubes are oriented vertically in a parallel-plate fashion, where the high-emissivity interior faces have restricted views to the environment and heat rejection is minimized. When the system heats up, the tubes actuate by twisting in opposing directions, bringing the panels to a horizontal position with the interior faces exposed to maximize heat rejection. When the system cools down, the tubes twist in reverse, restoring the panels to the vertical orientation where heat rejection is again minimized. This variable heat rejection system has the potential for achieving higher turndown ratios than those of current state-of-the-art systems. A benchtop prototype has been designed and tested to demonstrate actuation and to explore internal heat transfer effects. Prototype design, testing, and results are herein described.