Comparison of Liquid Water Content Measurement Technquies in an Icing Wind Tunnel

This paper compares the results of liquid water content measurements by various means in an icing wind tunnel. The techniques/instruments tested are the icing blade, a single rotating cylinder, the Johnson-Williams and CSIRO-King hot-wire probes, the Nevzorov LWC/TWC probe and the liquid water conte...

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Bibliographic Details
Main Author: Ide, Robert F.
Other Authors: NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CENTER
Format: Text
Language:English
Published: 1999
Subjects:
Aerodynamics
Snow
Ice and Permafrost
*ICE FORMATION
*WIND TUNNEL TESTS
MEASUREMENT
OPTICAL EQUIPMENT
PROBES
LIQUIDS
ARRAYS
BLADES
MOISTURE CONTENT
DROPS
AIRSPEED
ROTATION
SUPERCOOLING
SPECTROMETERS
FORWARD SCATTERING
DEICING SYSTEMS
AIRCRAFT ICING
LIQUID WATER CONTENT
Ice
permafrost
Online Access:http://www.dtic.mil/docs/citations/ADA371598
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA371598
Description
Summary:This paper compares the results of liquid water content measurements by various means in an icing wind tunnel. The techniques/instruments tested are the icing blade, a single rotating cylinder, the Johnson-Williams and CSIRO-King hot-wire probes, the Nevzorov LWC/TWC probe and the liquid water content calculated from the combined droplet distributions of two droplet sizing probes - the Forward Scattering Spectrometer probe and the Optical Array probe. A large range of icing conditions was used for this study. The liquid water content ranged from 0.1 to 1.25 g/cu m and the median volumetric droplet diameters (MVD) ranged from 10 to 270 micrometers. Airspeeds of 50 to 250 mph (22 to 112 m/s) were used. This study shows the degree of agreement between the various liquid water content measurement methods over the normal cloud MVD range of 10 to 50 micrometers and over several supercooled large droplet (SLD) conditions. It shows that the Nevzorov LWC/TWC instrument has the potential for measuring the LWC in SLD clouds as well as normal droplet size cloud conditions. It reveals a large disagreement between the droplet sizing probe results and the other methods. The implications and possible causes of this disagreement are discussed. Recommendations for additional investigations to resolve disagreements are included.

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