Molecular Beam Studies of Sulfur Hexafluoride Clustering in an Argon Carrier Gas from Both Free Jet and Laval Nozzle Sources.
Abstract
Experiments on adiabatic expansions of SF6 in an argon carrier gas reveal that is readily nucleates and grows in the small free jets and Laval nozzles used as molecular beam sources. One free jet orifice and one nozzle of approximately the same throat size were used in this work. Limits for the onset of clustering leading to intense 'molecular' beams have been determined by varying the intial pressure, initial temperature, SF6 mole fraction and gas expansion (and cooling) rate. As anticipated, the Laval nozzle is a much more efficient cluster generator than the free jet. High energy electron diffraction has been employed to ascertain the cluster size, crystalline structure (body centered cubic), and unit cell dimensions as functions of the initial conditions. Estimates of the cluster temperatures have been made from their cell dimensions. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1978
- Accession Number
- ADA061810
Entities
People
- Barry G. Deboer
- Gilbert D. Stein
- Sang Soo Kim
Organizations
- Northwestern University