基于NTC微珠状热敏电阻的稳态测量方法

稳态导热系数测量方法的原理和数学模型简单，但热源均温性要求高和测量时间长限制了稳态导热系数测量方法的实际应用。提出一种测量导热系数的新型微球法稳态热测量方法，建立对应的物理模型和试验方法。通过熔融共混法制备不同质量分数的石墨烯 石蜡复合相变材料，并采用微球法对不同质量分数的石墨烯 石蜡复合相变材料的导热系数进行测量。测量得到样品的导热系数分别为0.278 W/(m·K）(0%)、0.330 W/（m·K）(0.5%)、0.402 W/（m·K）(1%)、0.524 W/（m·K）(2%)、0.604 W/（m·K）(3%)、0.654 W/（m·K）(4%)和0.711 W/（m·K）(5%)。该方法具有微球体积小、热源均匀、测量快、样品制备简单等优点，可应用于实际工程中相变材料和液体的原位导热系数测量。

Steady state measurement method based on #br# NTC micro bead thermistor

The principle and mathematical model of steady state measurement method of thermal conductivity was simple. But the high requirement of heat source temperature uniformity and the long measurement time limit its practical application. A new microsphere method for steady state thermal measurement of thermal conductivity was proposed. The corresponding physical model and experimental method were established. Graphene paraffin phase change materials with different mass fractions were prepared by melt blending process. Moreover, the thermal conductivity of prepared samples was measured by the proposed microsphere method. The measured thermal conductivity of graphene paraffin phase change materials was 0.278 W/(m·K）(0%), 0.330 W/（m·K）(0.5%), 0.402 W/（m·K）(1%), 0.524 W/（m·K）(2%), 0.604 W/（m·K）(3%), 0.654 W/（m·K)(4%) and 0.711 W/(m·K)(5%), respectively. This method had many advantages, such as small volume of microspheres, uniform heat source, fast measurement, and simple sample preparation. It was applicable for the in situ thermal conductivity measurement of phase change materials and liquid in actual engineering.