动态法测量熔点附近热导率

Dynamic method for measuring thermal conductivity near melting point

相界面移动测量法,是动态测量熔盐热导率的一种方法。它是利用一维条件下相界面移动速率与热导率的代数关系,通过测量相界面移动速率来定量计算热导率。该方法要求实验平台满足一维导热及平板温度突然升高等物理条件,故合理设计优化加热装置成为减小实验误差的重要手段。采用电感加热,满足实验对加热装置高热流密度、快速控温的热环境要求。陶瓷圆管作为相变室,中部使用填充绝热棉及温度补偿方式尽量减小径向散热;上下部使用自制电感加热器包裹高温钢,提供两端面温差及温度突变。利用该装置,对溴化锌熔点附近热导率进行测试,并结合数值模拟减小测试误差。

Phase interface moving measurement is a method of dynamic measuring of thermal conductivity of molten salt.By using the algebraic relations between the graphic interface moving rate and the thermal conductivity rate under one-dimensional conditions,the thermal conductivity can be calculated quantitatively by measuring the rate of phase interface movement.This method requires the experimental platform to meet the physical conditions such as one-dimensional heat conduction and sudden increase in flat temperature,so rational design of optimal heating device is very important for the experimental error.Inductance heating was used to meets the thermal environment requirements of high heat flux and rapid temperature control.Ceramic tube was used as a phase-change room,and insulation cotton and temperature compensation were used in the middle part to minimize the radial heat dissipation,self-inductanced heater packed high-temperature steel were used in the upper and lower ends to provide the surface temperature difference and the temperature mutation.The thermal conductivity of zinc bromide near the melting point was measured using the device described above and numerical simulation were carried out to reduce the test error.