超临界CO_2中沉降颗粒气液双重规律研究  

Study on the gas and liquid duality law of settling particle in super-critical CO_2

作　　者：侯磊[1] 孙宝江[1] 王志远[1] 李庆建 

机构地区：[1]中国石油大学(华东)石油工程学院,青岛266580

出　　处：《水动力学研究与进展（A辑）》2015年第1期64-69,共6页Chinese Journal of Hydrodynamics

基　　金：国家自然基金(U1262202和51104172);中央高校基本科研业务费专项资金(12CX06026A)~~

摘　　要：通常认为超临界态流体具有气、液双重性,如黏度接近气态,密度接近液态。该文从超临界CO2(SC-CO2)密度、黏度角度出发,分别从黏度随温度变化规律、颗粒沉降受力分析、沉降速度与黏度关系三个角度对这一气、液双重性做了进一步探索,并研究其对SC-CO2动力学特性的影响。分析发现,压力一定条件下,存在一个临界温度值,SC-CO2黏度在临界值附近表现出了明显的气、液两态特性。通过对SC-CO2中沉降颗粒受力的数值计算结果分析发现,颗粒所受的浮力、附加质量力、Basset力均属同一数量级,在沉降加速初期起着重要作用,均不可忽略。在总结大量实验数据的基础上,绘制了颗粒平衡沉降速度与SC-CO2黏度的关系曲线,发现在黏度较低时,颗粒的沉降速度随黏度的增加而增加;当黏度较高时,沉降速度随黏度的增大而降低,具有气、液双重沉降规律。As all known, super-critical fluids usually have low viscosity close to gas and high density close to liquid. In this paper, this duality character is studied by analyzing the viscosity change with temperature, forces on the settling particle and terminal velocity change with the viscosity. All the work is trying to study how the duality character of super-critical CO2（SC-CO2） affects its dynamic character. There is a critical temperature around which the viscosity changes of SC-CO2 conform to both gas and liqu id laws in differ ent sides. By numerical calculation for th e forces on the settling par ticle, th e buoyancy, additional mass force and Basset force are at the same order of magnitude. Thus, none of them could be ignored at the very beginning of the settlement. Based on large number of experimental data, the relationship between terminal velocity and SC-CO2 viscosity indicates that the terminal velocity goes up with the increase of SC-CO2 viscosity when the viscosity is relatively low. Yet, at the relatively high viscosity situation, the terminal velocity will go down as the increase of SC-CO2 viscosity.

关 键 词：超临界二氧化碳 沉降规律 气、液双重性 实验研究 

分 类 号：TV142.1[水利工程—水力学及河流动力学]