Effects of coherent structures on nanoparticle coagulation and dispersion in a round jet

The discrete vortex method for gas flow and the moment method coupled with a unimodal lognormal particle size distribution were used to simulate the nanoparticle coagulation and dispersion in a round jet. The results show that the interface of the jet region and the outside rolls up to form coherent structures, which alters the particle concentrations and enhances the particle coagulation. The jet region of the particles mixture and the number of different particle sizes increase with increasing of the time, however, the number concentration of particles decreases in the jet region while increasing at its outside. The coherent structures play an important role in enhancing the particle coagulation and dispersion along the radial direction of jet, and make the particles disperse non-uniformly along the stream direction of jet. As the Schmidt number increases, the jet region of mixture of particles becomes narrower, and polydispersity turns unobvious, however, the particle number concentration grows accordingly. The gradient in particle size and the standard deviation of the particle size distribution increase along the radial direction of jet with increasing of the Damkohler number.