A small-scale experimental facility to study the formation and dynamics of droplets in the presence of aerosols particles

We present a new cloud chamber facility to study aerosol-droplet-cloud interaction together with initial experimental characterization. We demonstrate the formation of droplets with mm during a fast pressure drop event, which causes a temperature change and the nucleation of droplets on aerosol particles present in the chamber. The facility consists of the main cloud chamber (approx. 55 cm x 55 cm x 50 cm, m³), and an expansion chamber ( m³) used to lower the pressure. Water droplets ( mm) are generated in the main chamber, which is filled with moderately humid air, by causing a sudden pressure drop inside. The pressure, humidity, temperature, and aerosol concentration are monitored in the main chamber throughout the duration of the experiments. Droplet statistics like number, size, and speed are measured using an inline holographic system and a phase doppler anemometer. We present preliminary results of the formation, size, and dynamics of water droplets generated in the main chamber for a range of initial conditions. An overview of future planned experiments is briefly discussed.