航天器用记忆合金热开关的设计与理论分析

介绍了一种航天器热控制用记忆合金热开关的设计与分析。该热开关以形状记忆合金弹簧作为感温和驱动元件，当温度超过记忆合金材料的奥氏体相变点时，驱动元件开始变形并推动热开关闭合；温度低于记忆合金材料的马氏体相变点时，偏置弹簧将克服记忆合金元件的弹力，推动热开关使之断开。热开关结构为圆柱体，长度32mm，直径23mm。对热开关的力学参数、传热性能进行了分析计算，表明该热开关的闭合热阻为2．69K／W，断开热阻大于352．64K／W，闭合时间小于30min。

DESIGN AND THEORETICAL ANALYZES OF SHAPE MEMORY ALLOY HEAT SWITCH FOR SPACEFLIGHT

The paper presents a design and theoretical analyzes of heat switch which is based on shape memory alloy （SMA）for Spaceflight thermal control. The SMA elements in such actuators integrate both sensory and actuation functions. The SMA element start to change its shape and push heat switch to close when temperature exceeds austenite transformation point of SMA material; and while temperature decrease less than martensitic transformation point of SMA material, the bias spring is going to overcome thrust force of the SMA element and push heat switch to turn off. The structure of heat switch is cylindrical with the length of 32 mm, diameter of 23 mm. The analyzes of mechanical parameters and heat transfer performance show that the thermal resistance of this heat switch is about 2.69 K/W when close and more than 352.64 K/W when turn off, the time needed from＂OFF＂ state to ＂ON＂ state is less than 30 min.