圆球导热法测定粮食导热系数研究

采用圆球导热法测定了稻谷、小麦、玉米和大豆的导热系数,并对稳态时间、装样均匀性和水分迁移等影响试验准确性的因素进行了分析.结果表明,该方法测定粮食导热系数的稳定时间至少需要8～10h,通过内外球壁多个热电偶的电势差能确保装样均匀,水分含量分别为10.9%、10.1%、11.0%、6.9%的稻谷、小麦、玉米和大豆的导热系数分别为0.105 4、0.141 8、0.136 2、0.127 4 W/(m·℃),水分迁移对低水分粮食导热系数测定结果的影响可以忽略.

Determination of Thermal Conductivity of Grain by Spherical Measuring Technology

Spherical measuring technology was used to measure the thermal conductivities of paddy, wheat, corn, and soybean. The influencing factors for the accuracy of the experiment, such as steady state time, uniformity of grain loading and moisture migration were also analyzed. Results: A steady state time of at least 8 ～ 10h is needed in this method to achieve a steady state of grain. The uniformity of loading can be ensured through the potential difference of inner and out spherical. The thermal conductivities of paddy, wheat, corn, and soybean, with moisture content of 10.9% , 10.1% , 11.0% , 6.9% respectively, are 0.1054, 0.1418, 0.1362, 0.1274 W/(m·℃), respectively. The effect of moisture migration in the thermal conductivity measure of grain with low moisture content can be neglected.