Evaluating a Cloud Chamber in Controlling Coagulation and Wall Losses at High Particle Loads

NEVIL FRANCO, Kyle Gorkowski, Katherine Benedict, Los Alamos National Laboratory

     Abstract Number: 175
     Working Group: Instrumentation and Methods

Abstract
In events such as wildfires and explosions, high concentrations of particles rapidly coagulate at rates that are sensitive to particle shape and surface adhesion. In these concentrated plumes, assumptions based on spherical particles breakdown due to the abundance of chain-like soot particles. Los Alamos National Laboratory’s new cloud chamber was designed to address the blind spot on second-order effects of coagulation in dense plumes of aerosols. Initial experiments in the 900L stainless steel chamber were conducted without humidity to characterize the particle wall loss. In these dry experiments, different types of aerosols were used to quantify the rates of deposition to the walls using a particle size and time-dependent formula fitted with data from aerosol size measuring instruments. Sodium chloride, sucrose, PSL, dust, and smoke were all introduced separately to the chamber at low and high concentrations. Preliminary results show that aerosols are lost to the walls and dilution in the chamber in relatively short time scales. This study lays the foundation for future coagulation experiments at elevated humidity and supersaturation conditions to characterize the influence of particle shape on coagulation and cloud parameters.