多尺寸颗粒堆积多孔介质通道内流动特性研究

Experimental Studies on the Flow Characteristics in Porous Beds Packed With Multi-sizes Particles

基于美国桑迪亚国家实验室(Sandia National Laboratory)利用反应堆熔融材料UO_2进行堆内实验获得的碎片床尺寸分布,采用不同尺寸的玻璃圆球和砂石颗粒按照相似的颗粒尺寸分布,分别构建了多尺寸球形颗粒混合堆积床和砂石堆积颗粒床,实验研究了单相和气-水两相竖直向上流过颗粒堆积床时的流动阻力特性。研究结果表明,具有宽广范围尺寸分布的颗粒堆积床,其有效直径的大小受颗粒形状的影响较小;相似尺寸分布的颗粒堆积床的有效直径十分接近。基于单相实验和Ergun方程获得的多尺寸颗粒堆积床的有效直径,其两相流动阻力压降与Reed模型的计算值吻合较好。

Based on the size distribution of particles from the in-pile experiments with UO2 in Sandia National Laboratory of USA,the test porous beds packed with multi-size spheres and sands particles are designed and constructed,which have the similar size distribution among them.The single and two phase flow tests are performed and the flow resistance characteristics are studied when single and two phase flow upward the packed beds.The results show that for a porous bed packed with various size particles,the shapes of particles have less influences on the effective diameter,and the approximate effective diameters can be obtained from the packed beds with the similar particles sizes distribution.Employing the effective diameter of bed with multi-size particles derived from the Ergun equation,the calculation results from Reed model predict well the measured pressure drops of the two phase flow.