A Simplified Model of Predicting SO2 Absorption by Single Atmospheric Raindrops with Chemical Dissociation and Internal Circulation

Abstract

A simplified model of predicting chemical SO 2 absorption by single freely falling raindrops with internal circulation in the atmosphere is developed in the present study. By multiplying a modification factor α into the model of interfacial velocity established from creeping flow, it is found that the relative error between the simplified model and the two-phase simulation method is less than 4%. Accordingly, the simplified model enables us to simulate the atmospheric SO 2 absorption process with less computational effort and without losing accuracy. The simulated results indicate that the dissociation of H 2 SO 3 governs the mass transfer process and the concentration of HSO 3 − is by far larger than those of SO 3 2− and H 2 SO 3 . As a result, the chemical absorption takes a much longer period of time to achieve the uptake process. Specifically, for the raindrop radius in the range of 200-500 μm, the absorption time of chemical absorption is larger than that of physical absorption by the factors of 70-290. From the perspective of characteristic time, mass diffusion is the controlling mechanism for SO 2 absorption. When chemical absorption is carried out, the absorption period is 28-33 folds of the characteristic time of mass diffusion, implying that the former is always larger than the latter by over an order of magnitude.

Characterization of Transient CO2 Transport in Two Convecting Aerosol Droplets in Tandem

“…Meanwhile, Fig. 4(b) demonstrates the comparison of dimensionless absorption amount of SO 2 by a water droplet at Re = 1.287 between the present study and the results of Chen (2001) and Chen et al (2011b) . Figs.…”

“…From the above literature review, it is figured out that the topics of CO 2 and other gas species absorbed by single droplets have been studied extensively (Adewuyi and Carmichael, 1982;Ma et al, 2005;Chen, 2006;Elperin et al, 2010;Chen et al, 2011b). In fact, CO 2 uptake by liquid absorbents also plays an important role in carbon capture and storage (Yu et al, 2012).…”

Flow Dynamics and PM2.5 Deposition in Healthy and Asthmatic Airways at Different Inhalation Statuses

“…However, to the authors' knowledge, investigations on airflow and particle deposition patterns in asthmatic human airways under three different transient breathing conditions have not been performed yet. Over the past several decades, computational fluid dynamics (CFD) has become an important tool to predict aerosol physics (Chen, 2001a, b;Chen et al, 2011Chen et al, , 2014. For these reasons, PM 2.5 deposition in generations 10 and 11 (G10 and G11) under the transient breathing conditions and the Weibel's airway model for healthy and asthmatic airways were investigated numerically in this study.…”

Minimum Collection Efficiency Particle Diameter during Precipitation as a Function of Rain Intensity

“…Wet deposition of aerosol particles is an important removal mechanism that serves to maintain a balance between atmospheric sources and sinks (Maria and Russell, 2005;Chen et al, 2011). The scavenging of atmospheric aerosols by the capture of raindrops, called below-cloud scavenging, is a wet deposition process (Tiwari et al, 2012).…”