Nucleation simulations using the fluid dynamics software FLUENT with the fine particle model FPM

Area of Science:

• Physical Chemistry
• Chemical Engineering
• Computational Fluid Dynamics

Background:

• Classical nucleation theory often underestimates nucleation rates for alcohol vapors.
• Accurate simulation of nucleation phenomena is crucial for understanding aerosol formation and atmospheric processes.

Purpose of the Study:

• To assess the capability of the FLUENT-FPM software package in simulating homogeneous nucleation experiments.
• To compare FPM simulations with experimental data and an established model (femtube2).

Main Methods:

• Verification of the FPM condensation routine using the NEWALC code.
• Simulation of homogeneous nucleation of n-butanol, n-pentanol, and n-hexanol in a laminar flow diffusion chamber (LFDC).
• Comparison of FPM results against experimental data and the femtube2 model.

Main Results:

• FPM underestimates particle production by several orders of magnitude, though the underestimation factor is constant per nucleation isotherm.
• FPM reproduces experimental trends in nucleated particle concentration (N) dependence on flow rate.
• Corrected FPM simulations successfully model experimentally observed vapor depletion effects.
• FPM predicts lower saturation ratios than the femtube2 model, with significant differences in vapor depletion behavior.
• FPM simulations confirm the carrier gas effect previously identified by Lihavainen and Viisanen (2001).

Conclusions:

• While FPM underestimates nucleation rates, it captures key experimental behaviors and can be calibrated to simulate vapor depletion.
• FPM provides a valuable tool for studying nucleation, but its predictions require careful comparison with experimental data and other models.
• The study highlights the importance of accounting for vapor depletion and carrier gas effects in nucleation simulations.