Nitrogen Condensation in a Sonic Orifice Expansion Flow

Abstract

Approved for public release; distribution unlimited. 17. DISTRIBUTION STATEMENT <ol III* obiltact entered In Black 29, it dtttoieni from Report) IB. SUPPLEMENTARY NOTES Available in DDC. WORDS (Contlnü j nitrogen condensat lice flow expansion :ontlrnirmarevereo eide It *-] Rayl« tion^>^ eleci naceemety end Identify by block number) leigh scattering lectron beam fluorescence measurement 20. ABSTRACT (Continue on rarer» elde It neceeeery and identity by block numl»rj Homogeneous condensation of nitrogen in hypersonic expansions from a sonic orifice source was investigated using both Rayleigb scattering and electron beam fluorescence diagnostics. Using a 3-mm orifice, the source pressure range of 100 to 4000 torr was investigated for a 300 K source temperature. Electron beam measurements of the rotational temperature, TR, of nitrogen (N2) were used to determine onset of condensation, and both radial and axial DD ,: FORM AH 73 1473 EDITION OF 1 MOV «S tS OBSOLETE UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE fWhan Dele Bnlortd) UNCLASSIFIED SECURITY CLASSIFICATION OF TmS PAQEpWran Dfa Eniirtd) 20. Continued. surveys of T R were performed. Similar electron beam measurements were performed for source temperatures of 116 K and 133 K for one pressure value. Rayleigh scattering measurements were used to observe both onset of condensation and growth of clusters along the centerline, and estimates of mole or mass fractions of condensate were obtained using both diagnostic techniques. Previously published supersaturation ratios of N 2 determined by other investigators were significantly larger than the present results which observed onset earlier in the flow field. UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGEfWian Data Enf.r«0

Argon Condensation in Free-Jet Expansions

“…5) of the monomer flow speed using mass spectrometric methods have enabled the final mass fraction of condensate to be determined, and the electron beam fluorescence method (Ref. 6) has been applied to the task of determining condensate mass fractions for the far field, low-density region of nitrogen (N2) condensing flows. Moreover, Rayleigh scattering measurements (Ref.…”

“…Details of the optical apertures used to reduce background scattering are presented in Ref. 6 and will not be repeated here. An International Telephone and Telegraph (ITT) FW130 photomultiplier tube cooled to -26°C was used for the photon counting detection method.…”