ISSN Online: 2688-7231
ISBN Online: 978-1-56700-524-0
Proceedings of the 26thNational and 4th International ISHMT-ASTFE Heat and Mass Transfer Conference December 17-20, 2021, IIT Madras, Chennai-600036, Tamil Nadu, India
Parametric Investigation of the Below-cloud Scavenging of Atmospheric Aerosols by Raindrops
The study presents a parametric investigation on the scavenging of atmospheric aerosols by the raindrops between clouds and the ground. A well-established governing mathematical model for scavenging action combined with certain parametric models has been used. The model has been solved to investigate the influence of raindrop-based parameters (number concentration, diameter, velocity), aerosol-based parameters (particle diameter, aerosol cloud height), and meteorological parameters (temperature, pressure, air viscosity; which in turn depend on the altitude of scavenging) on the scavenging performance. It has been found that in order to maintain the desired scavenging performance despite a decrement in the size of aerosol particles, a higher number concentration or diameter of raindrops is required. For a given rain intensity, smaller raindrops have been found to provide better scavenging performance. Also, a rise in the altitude at which the scavenging takes place and increase in the height of aerosol cloud have been observed to improve the scavenging performance. Though an increase in raindrop diameter also improves the overall scavenging performance, the exact nature of variation depends on the size of aerosol particles and the number concentration of raindrops.