摘要
为了研究反应堆严重事故后分层结构碎片床的流动阻力特性,使用4种尺寸球形颗粒构建了 3种颗粒堆积床,分别是颗粒均匀堆积床、水平分层颗粒堆积床和竖直分层颗粒堆积床。基于3种颗粒堆积床,开展了单相/两相流动实验,对比分析了不同堆积结构颗粒床内的流动阻力特性。研究结果表明:对水平分层结构,当下层为小颗粒、上层为大颗粒时,分层结构对流动阻力压降的影响可以忽略,堆积床上下层内的流动阻力压降和相同尺寸的颗粒均匀堆积床内的流动阻力压降基本相同;当下层为大颗粒、上层为小颗粒时,分层结构显著提高了上层小颗粒堆积床内的流动阻力压降,在最大实验流速工况下,上层小颗粒堆积床的流动阻力压降约是相同尺寸颗粒均匀堆积床的1.25倍,而下层大颗粒床内的阻力压降基本不变。竖直分层颗粒堆积床内存在横向流动,导致小颗粒堆积层内流动阻力压降降低而大颗粒层的流动阻力压降升高。研究结果对完善多孔介质结构内的流动阻力分析具有重要意义。
To study the characteristics of flow resistances in a stratified debris packed bed after severe accident in nuclear reactor,the paper reports an experimental study on the pressure drops of single-/two-phase flow through the vertically and horizontally stratified beds.Three types of particular beds were designed and constructed with different sizes of glass spheres.Type-1 bed is a homogeneous bed consisting of single size spheres.While Type-2 bed and Type-3 bed are stratified beds with the structure of horizontal stratification and vertical stratification,respectively.Both single- and two-phases flow tests were carried out,and the pressure drops were measured.The results showed that,for a horizontally stratified bed with larger particles atop and smaller particles down,the pressure drops in each part of horizontally stratified bed are almost the same as those of homogeneous bed packed with the same size spheres.It seems that the stratification has less effect on the pressure drops in the stratified bed.While for the horizontally stratified bed with fine particles atop and coarse particles down,it can be found that the pressure drops in top layer are higher than those of homogenous bed composed of the same size particles;the pressure drop is about 1.25 times that of homogenous bed at the highest test flowrate;and the pressure drops of bottom layer with coarse particles are similar with those of homogenous bed packed with the same coarse particles.For the vertically stratified bed packed with different size particles,it is believed that lateral flows exist in the vertically stratified bed,which will decrease the pressure drops in the layer with smaller particles but increase the pressure drops in the layer composed of coarser particles.The experimental results provide a reference to improve the analysis on the flow resistance in porous media.
作者
李良星
王凯琳
谢伟
张双宝
LI Liangxing;WANG Kailin;XIE Wei;ZHANG Shuangbao(State Key Laboratory of Multiphase Flow in Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2019年第7期60-66,117,共8页
Journal of Xi'an Jiaotong University
基金
国家自然科学基金资助项目(51406143)
关键词
分层颗粒堆积床
流动特性
阻力压降
多孔介质
stratified packed bed
flow characteristics
pressure drop
porous media
