An Axial-Flow Cyclone for Aircraft-Based Cloud Water Sampling

A new aircraft-based cloud water collection system has been developed to provide samples of cloud water for chemical analysis. The collection system makes use of centrifugal separation in an axial-flow cyclone to remove cloud drops from the airstream. An automated sample storage system allows up to seven independent samples to be obtained during a single research flight. The entire collection system is housed in a Particle Measurement Systems (PMS) canister to permit the collector to be used on a range of research aircraft without extensive modification to the collector or the aircraft structure. Computational fluid dynamics (CFD) analysis was used extensively throughout the development of the new collector for component design and to predict internal flow dynamics. CFD-based cloud drop trajectory simulations provided an estimate of collection efficiency as a function of drop size. Based on the numerical modeling, the 50% cut diameter was predicted to be 8 μm. Through a quantitative laboratory ca...