NASA LogoNTRSNTRS - NASA Technical Reports ServerSearchmore_vertCollectionsAboutNewsHelpLogin Back to ResultsIsokinetic TWC Evaporator Probe: Calculations and Systemic Uncertainty AnalysisA new Isokinetic Total Water Content Evaporator (IKP2) was downsized from a prototype instrument, specifically to make airborne measurements of hydrometeor total water content (TWC) in deep tropical convective clouds to assess the new ice crystal Appendix D icing envelope. The probe underwent numerous laboratory and wind tunnel investigations to ensure reliable operation under the difficult high altitude/speed/TWC conditions under which other TWC instruments have been known to either fail, or have unknown performance characteristics and the results are presented in a companion paper (Ref. 1). This paper presents the equations used to determine the total water content (TWC) of the sampled atmosphere from the values measured by the IKP2 or necessary ancillary data from other instruments. The uncertainty in the final TWC is determined by propagating the uncertainty in the measured values through the calculations to the final result. Two techniques were used and the results compared. The first is a typical analytical method of propagating uncertainty and the second performs a Monte Carlo simulation. The results are very similar with differences that are insignificant for practical purposes. The uncertainty is between 2 and 3 percent at most practical operating conditions. The capture efficiency of the IKP2 was also examined based on a computational fluid dynamic simulation of the original IKP and scaled down to the IKP2. Particles above 24 micrometers were found to have a capture efficiency greater than 99 percent at all operating conditions.Document ID20160013857Acquisition SourceGlenn Research CenterDocument TypeTechnical Memorandum (TM)AuthorsDavison, Craig R.*(National Research Council of Canada Ottawa, Ontario, Canada)*Strapp, John W.*(Met Analytics Aurora, Ontario, Canada)*Lilie, Lyle E.*(Science Engineering Associates, Inc. )*Ratvasky, Thomas P.*(NASA Glenn Research Center Cleveland, OH United States)*Dumont, Christopher*(William J. Hughes Technical Center Atlantic City, NJ, United States)*Date AcquiredNovember 30, 2016Publication DateOctober 1, 2016Subject CategoryAerodynamicsReport/Patent NumberNASA/TM-2016-219150GRC-E-DAA-TN33385AIAA Paper 2016-4060E-19273Meeting InformationMeeting: Atmospheric and Space Environments ConferenceLocation: Washington, DCCountry: United StatesStart Date: June 13, 2016End Date: June 17, 2016Sponsors:American Inst. of Aeronautics and AstronauticsFunding Number(s)WBS: WBS 147016.03.03.02.14.01Distribution LimitsPublicCopyrightPublic Use Permitted.KeywordsMeteorological InstrumentAircraft IcingWind Tunnel TestsAvailable DownloadsNameType20160013857.pdfSTIcloud_downloadcontent_copyvisibilityRelated RecordsIDRelationTitle20170000240See AlsoIsokinetic TWC Evaporator Probe: Calculations and Systemic Uncertainty Analysisvisibility_offNo Preview Available
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