A New Wind Tunnel Facility for Ice Crystal Icing Experiments 2019-01-1926

The design and characterization of a new ice crystal icing wind tunnel facility is introduced through this work. The arrangement proposed in this work involves water droplet freeze-out using liquid nitrogen evaporation followed by natural particle melting through dilution with warm air. The viability of the concept was first demonstrated theoretically using a conservation of energy analysis. Thermodynamic performance of the facility is dictated largely by the availability of the liquid nitrogen, and in order to establish a facility with modest operating costs, the proposed operation specified using a maximum of 20 liter of liquid nitrogen per run with a maximum duration of two minutes. The target operating conditions for the facility were: flow speed around 50 m/s, temperatures around 0 °C, and total water content up to 10 g/m³ with melting ratio up to 0.2. Experimental results have demonstrated a generally favorable agreement with the energy equation analysis, and with results from Computational Fluid Dynamics (CFD) simulations. Experiments have demonstrate sufficient uniformity of flow speed and temperature for the facility to be regarded as a viable wind tunnel for ice crystal icing experimentation. Although the measured flow speed was around 28 m/s, this can be readily increased to achieve the target condition in future work.