Shock Waves

, Volume 12, Issue 6, pp 435–441 | Cite as

Time-of-flight diode-laser velocimeter using a locally seeded atomic absorber: Application in a pulse detonation engine

  • S. T. Sanders
  • D. W. Mattison
  • J. B. Jeffries
  • R. K. Hanson
Original Paper

Abstract.

A diode-laser velocimeter based on atomic absorption spectroscopy has been developed and applied to a pulse detonation engine (PDE). The velocimeter uses a salt-coated sting to seed an atomic absorber at any desired location and a single, fixed-wavelength diode laser to monitor the absorber's presence downstream of the sting. Salt particles stripped from the sting tend to form distinct "clouds" of the atomic absorber rather than a uniform absorber stream. Gas velocity is inferred by measuring the time of flight of these clouds over a known distance. The properties of the salt coating can, in principle, be adjusted to tailor the velocimeter to a variety of flows and optimize its time response. In a PDE operating on C2H4 / O2, CsCl salt was seeded from a 150 \(\mu \)m diameter sting, and the D2 transition of atomic Cs near 852 nm was probed. Gas velocity histories, spanning 0-1000 m/s over a duration of \(\sim \) 6 ms, were recorded in the PDE and used to validate detonation models. Images obtained using an array of stings in a PDE are presented to demonstrate the potential for multidimensional velocimetry and to provide insight into the physics of the salt seeding.

Keywords:

Velocimetry Cesium Absorption Pulse detonation engine 

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Copyright information

© Springer-Verlag Berlin/Heidelberg 2003

Authors and Affiliations

  • S. T. Sanders
    • 1
  • D. W. Mattison
    • 1
  • J. B. Jeffries
    • 1
  • R. K. Hanson
    • 1
  1. 1.Mechanical Engineering DepartmentStanford UniversityStanfordUSA

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