Metal Nanoparticle Nucleation: The Effects of Surface Tension and Fluid Turbulence

Jun Liu (1), Sean Garrick (1)

(1) University of Minnesota, Minneapolis

     Abstract Number: 836
     Last modified: August 6, 2010

Abstract
The rising need for clean, renewable energy sources has led to recent studies on hydrogen production via hydrolysis of zinc nanoparticles. Aerosol or gas-phase processes are favored in many industrial applications due to its advantage in controlling particle size distribution and the resultant chemical conversion. The properties of the resulting aerosol is essential to the chemical reaction process. Optimization of reactor design as well as the operating conditions are needed to assure high yield. An accurate description of the nucleation process is essential if one wants to better control particle properties. Our interest will focus on the homogeneous nucleation in practical flows. Direct numerical simulation of homogeneous metal vapor nucleation in laminar and turbulent flows are performed for a variety of metals. The flows consist of hot metal vapor issuing into cooler inert gas. As the metal vapor cools, nanoparticles form and are transported throughout the flow-field. Homogeneous nucleation is simulated using classical nucleation theory and two approaches to representing the surface tension. The effects of three-dimensional turbulent mixing are also analyzed. The results suggest that the effects of surface tension variation with temperature and critical diameter. Additionally, these dynamics can be exploited by controlling the transition from laminar to turbulent flows.