The effects of turbulence on nanoparticle nucleation are studied using a combination of fully resolved and large-scale quantities from direct numerical simulations. Growth of these particles is considered by Brownian coagulation. Three simulations are performed using a single Reynolds number and vapor mass fraction. In addition to the direct numerical simulation, we perform hybrid simulations in which fluid, thermal, and scalar transport are fully resolved, while the thermo-chemical variables used in predicting nanoparticle nucleation are filtered. This allows us to elucidate the effects of the unresolved or sub-grid scale (SGS) scalars on the formation of metal particles. The results show that the saturation ratio-representative of the driving force towards particle nucleation-is over-predicted when the SGS interactions are neglected. This results in increased nucleation-particle formation occurs both further upstream and at greater rates. While the SGS interactions act to both increase and decrease particle formation, the tendency to decrease nucleation is dominant.
Bibliographical noteFunding Information:
Financial support for this work was provided by the Institute for Renewable Energy and the Institute on the Environment at the University of Minnesota. All computations were performed at the Minnesota Supercomputer Institute.