Abstract:

A lab-scale Gas-Liquid Cross-Flow Array system (GLCA) was built up to investigate the effect of velocity, arrangement of liquid columns and particle size on separation efficiency of particles in gas by a continuous and regular liquid column array of water. These continuously falling water liquid columns were perpendicular streams to the dusty gas flow, so that particles could be captured by the water streams due to inertial, diffusion and interception mechanism. The experimental results showed that the separation efficiency decreased with increase of the specific surface area and particle size whereas the effect of velocity in the experimental range was unremarkable. Under the optimal column arrangement, a separation efficiency of 37.3%, 43.9% and 99% was achieved for particle size of 0.1, 1 and 10 μm, respectively, at an air velocity of 1 1 m·s^-1 after 162 unit rows. A prediction formula was proposed for extrapolative calculation of grade efficiency of separation and expected pressure drop of a given particle size as a function of the unit number of liquid column arrays. As an example, total pressure drop was expected no more than 300 Pa for 0.4 μm particles at 95% separation efficiency. Large eddy simulation (LES) at the optimized experimental conditions yielded the numeric simulation in good agreement with the experimental data and thus verified prediction formula of separation efficiency. With this model, it is possible to predict the performance of GLCA although other driving forces would be taken into account, e.g. the thermophoretic force and the convection caused by vapor condensation and chemical reactions.

Key words: multiphase flow, gas liquid cross-flow array, grade efficiency, particle, numerical simulation

摘要：

对采用以水为介质吸收含尘气体中颗粒物的气液交叉流系统（GLCA）进行实验研究，考察了气速、液柱排布方式、粒径等因素对脱除率的影响。结果表明，随着液柱比表面积和颗粒粒径的增加，脱除率逐渐上升；在实验条件下气速对脱除率影响较小。在最优液柱排布方式下，经过162单元液柱排后，粒径为0.2、1、10 μm的颗粒分别取得了37.3%、43.9%、99%的脱除率。给出了用于外推计算分级效率和压降随单元液柱排数变化的公式，当粒径为0.4 μm的颗粒预测脱除率达到95%时系统的总压降不超过300 Pa。采用大涡模型对最优工况进行数值模拟，模拟结果与实验数据吻合良好，以此验证了所给脱除率计算公式。

关键词: 多相流, 气液交叉流, 分级效率, 粒子, 数值模拟