气液并流吸收近界面浓度分布不稳定性实时观测

Real-time measurement of unstable concentration distribution near interface for gas-liquid cocurrent absorption

气液自由界面附近的瞬时浓度分布信息对于理解相际传质动力学很重要。利用激光全息干涉测量系统分别对乙醇、甲醇并流吸收CO2过程中液相内近界面的摩尔分数分布进行了实时观测。研究表明,水平槽道内气液流动传质过程中液相内的不稳定性现象是普遍存在的。它主要包括界面湍动和周期性脉冲爆发2种形式。当传质达到稳态时近界面CO2摩尔分数的分布结果表明,流场内存在着微弱的摩尔分数波动。吸收体系的性质和流速直接影响传质推动力的大小,从而决定摩尔分数波动的强度及深度。

Experimental data of the concentration field near free gas-liquid interface with high spatiotemporal resolution is important for the comprehension of mass transfer kinetics. The real-time laser holographic interferometry was used to investigate respectively the evolutions of concentration distributions going with absorptions of CO2 by ethanol and methanol for cocurrent flow. The results show that the instability phenomena in the liquid exist universally during mass transfer. It mainly includes two forms of near-interface turbulence and periodic burst. And the steady-state CO2 mass fraction distributions inside the liquid phase close to the interface gained under different conditions demonstrate that mass fraction fluctuation is nearly relational to the mass transfer impetus affected by the physics property and velocity of the absorbent.