Smart distributed marine spray networks for atmospheric humidification: Droplet evaporation dynamics and nanotechnology-relevant aerosol formation

Abstract

The arid and semi-arid lands of Iraq are prone to severe hydrological strain and growing desertification. This study investigates the scientific possibility of establishing a widespread coastal evaporation system for seawater sprays to increase water evaporation in the atmospheric boundary layer and decrease the level of condensation during suitable atmospheric conditions. This paper combines the Schiller-Naumann hydrodynamic drag equations with the Ranz-Marshall convection-enhanced mass transfer model to overcome the standard simplifications of classical projectiles. The nanotechnology-related aspects of the proposed system are also considered by examining the potential formation of fine and nanoscale marine aerosols during seawater evaporation. Particular attention is given to the relationship between initial droplet dimensions, residual salt-particle formation, and their possible implications for atmospheric transport and environmental monitoring. The results show that the evaporation efficiency of droplets between 200 and 500 µm is highly sensitive to atmospheric drag. The efficiency is above 80% for droplets smaller than 200 microns. For the 500 µm droplets, however, it goes down to about 21.4% because they reach terminal velocity earlier. For constant-mass-flow models, concentrated fields show a local vapor choke of approximately 7,300 m³/day per 1000 m² of frontal area. This limitation forces you to work with a distributed geometry. We also followed the movement of moisture in space and time by using the ERA5 dataset and Lagrangian models so that we could see where the moisture is deposited. Calculations of hard deposits show that evaporation can produce about 1,058 metric tons of dry salt per m³/second of seawater with particles ranging in size from 50 to 130 microns. This adds a lot to the aerosol population in the atmosphere, which includes nanoparticles, and changes the levels of PM_2-5. To limit operations that enable the most efficient transport of moisture, thus keeping coastal salinity and local air quality at high levels, the Moisture Opportunity Index (MOI) is created.