Particle Size Calibration Testing in the NASA Propulsion System Laboratory

Abstract

The particle size characterization portion of the 2017 Propulsion Systems Laboratory Cloud Calibration is described. The work focuses on characterizing the particle size distribution of the icing cloud as a function of simulated atmospheric conditions. These results will aid in upcoming ice crystal and supercooled liquid icing tests in PSL. Measurements acquired with the Phase Doppler Interferometer and High Speed Imaging instruments are presented. Experimental results indicate that the particle size distribution is primarily a function nozzle air and water pressures, and that air speed is not a significant effect for ice crystal clouds in PSL and both thermodynamic conditions and air speed are not significant effects for supercooled liquid water clouds in PSL. I. Nomenclature∆p = Nozzle Water-Air Differential Pressure dv0.10 = 10 th Percentile Cumulative Volume Diameter dv0.25 = 25 th Percentile Cumulative Volume Diameter dv0.50 = 50 th Percentile Cumulative Volume Diameter, Median Volumetric Diameter dv0.75 = 25 th Percentile Cumulative Volume Diameter dv0.90 = 90 th Percentile Cumulative Volume Diameter HSI = High Speed Imaging ICI = Ice Crystal Icing IKP2 = Isokinetic Probe LWC = Liquid Water Content MW = Multi-Element Probe (commonly known as the "Multi-Wire") ND = Number Density pAIR = Nozzle Air Pressure PDI = Phase Doppler Interferometer ϕPL = Plenum Relative Humidity Upstream of the Spray Bars

Update on the NASA Glenn Propulsion Systems Lab Icing and Ice Crystal Cloud Characterization - 2017

“…Further detail of the particle size distribution acquisition and final results of the can be found in Ref. [23], while a description of the air temperature and humidity, both cloud off and cloud on, can be found in Ref. [22].…”

“…Greater detail of the HSI and PDI systems, as well as the PSD results from this test are being presented in a companion paper, Ref. [23].…”

“…A more complete description of the particle size acquisition, data processing, and final PSD results can be found in a companion paper, Ref. [23]. Reported here are only the initial PSD results provided in a timely fashion to begin creating calibration curves for the Median Volumetric Diameter, MVD in support of the engine test.…”

“…Raw values correspond to the real-time results, pvc corresponds to probe-volume corrected results, and fit refers to a Generalized Extreme Value (GEV) probability function (PDF) being applied to the count distribution to account for low counting statistics at the higher end of the size spectrum, Ref. [23]. After consultation with the wider team, it was decided that while the fit version was promising, there was not enough data to defend its use at the time the curves had to be generated.…”

Ice-Crystal Icing Accretion Studies at the NASA Propulsion Systems Laboratory

“…The PSD was measured using the Artium HSI and PDI probes. Details of the HSI and PDI techniques used to extract the PSD are described elsewhere [19].…”