导热系数对含空穴椭球形颗粒堆传热性能影响

Effects of thermal conductivity on heat transfer performance of ellipsoidal particle heap containing vacancy

针对堆积的颗粒常存在空穴的现象,构建了含空穴的椭球形颗粒堆稳态传热模型,研究了颗粒导热系数对含空穴椭球形颗粒堆传热特性的影响。研究结果表明:随着颗粒导热系数的增加,颗粒堆的平均热流密度增加,表观热阻减小;随着颗粒导热系数的增加,空穴对颗粒堆传热性能的影响程度增加,平均热流密度相对变化率和表观热阻相对变化率增加;随着颗粒导热系数的增加,空穴影响颗粒堆传热的区域面积越大,随着导热系数由0.5 W/(m·K)增至50 W/(m·K),空穴影响区域比由1.599%增至6.058%。

Considering that vacancies often exist in accumulated particles,a steady-state heat transfer model of a vacancy-containing ellipsoidal particle heap was constructed to study the effects of the thermal conductivity of the particles on the primary heat transfer performance of the ellipsoidal particles containing vacancy.The results show the following three rules.Firstly,as the thermal conductivity of the particles increases,the average heat flux of the particle heap increases and the apparent thermal resistance decreases.Secondly,as the thermal conductivity of the particles increases,the degree of influence of vacancy on the particle heap increases,and the relative rate of change in average heat flux and the relative rate of change in apparent thermal resistance increase.Thirdly,the area of influence by vacancy on the interior of the particle heap is distributed in a ring shape,which increases with the increase of thermal conductivity.For instance,as the thermal conductivity increases from 0.5 W/(m·K)to 50 W/(m·K),the vacancy affected area ratio increases from 1.599%to 6.058%.