We developed a continuous flow diffusion (CFD) chamber technique for studying ice nucleating aerosol particles in laboratory experiments and from airborne platforms. This page gives some information about the airborne CFD, with plots of the sampling conditions, illustrations of how the CFD was configured in different aircraft, and photos of the CFD. Other information can be found under field projects: Ice Nuclei Measurements in the Arctic and Lake-ICE SnowBand project

Computations and Modeling

Calculations of air flow, temperature, humidity, and particle growth in the space between the two ice-coated walls were first made assuming flat parallel-plate walls and steady-state conditions. Temperature and supersaturation range are determined by wall temperatures and air flow. Two plots are shown, for relatively warm temperatures (-10 to -30°C) and then for colder temperatures (-40 to -60°C).

The profile of air velocity in the CFD chamber is based on analytical solutions for the steady state. This approach is used for real-time operation of the chambers. To understand the evolution of the flow and thermodynamic fields, we are also using computational fluid dynamics modeling. The distance between the walls determines how quickly the air adjusts to the boundary conditions, as illustrated by modeling examples.

Air Flow and Inlet Impactors

Equipment

Assorted Drawings and Photos