1 research outputs found
Computational Fluid Dynamics of a Cylindrical Nucleation Flow Reactor with Detailed Cluster Thermodynamics
Particle formation and growth with H<sub>2</sub>SO<sub>4</sub> molecules
in an axially symmetric flow reactor was simulated with computational
fluid dynamics. A warm (∼310 K) gas containing H<sub>2</sub>SO<sub>4</sub> flows into a cooled section (296 K) that induces particle
formation. The fluid dynamics gives flow fields, temperatures, and
reactant and cluster distributions. Particle formation and growth
are simulated with detailed H<sub>2</sub>SO<sub>4</sub> cluster kinetics
with chemistry based on measured small cluster thermodynamics and
on bulk thermodynamics for large clusters. Results show that particle
number densities have power law dependencies on sulfuric acid of ∼7,
in accord with the thermodynamics of the cluster chemistry. The region
where particle formation rates are largest has a temperature that
is within 3 K of the wall. Additional simulations show that the H<sub>2</sub>SO<sub>4</sub> concentration in this region is 5 to 10 times
greater than the measured H<sub>2</sub>SO<sub>4</sub>: this information
allows for direct comparisons of experiment and theory. Experiments
where ammonia was added as a third nucleating species were simulated
with a three-dimensional model. Ammonia was dispersed quickly and
particle formation during this mixing was seen to be low. Downstream
of the initial mixing region, however, ammonia greatly affected particle
formation