Abstract-
Laser-based spectroscopic sensing provides powerful tools for engineers seeking
to study or control gaseous and multi-phase flowfields and processes. The
growing availability, affordability and ease of use of tunable cw laser
sources, particularly in the near-infrared (NIR) region where laser development
has been driven by telecommunications needs, has led to a family of new sensing
techniques which are both simple and economical. Of particular use are
diagnostic schemes based on spectrally resolved absorption which can be used
to monitor a wide range of common species (molecular and atomic) as well as
common flowfield properties such as temperature, pressure, mass flux, etc.
These diagnostic schemes, based primarily on Beer's law absorption, are
generally non-intrusive and can be used for remote measurements in hostile
environments by transmitting the laser light through optical fibers. This
presentation will provide current examples of diode-laser-based absorption
sensing drawn from a variety of applications: modern aero-propulsion engines,
inlet mass flux for aero-engines, characterization of a high-temperature
arc-jet, and wavelength-multiplexed sensing of evaporating droplets in a new
aerosol shock tube. In addition to their use in basic research and
development, these sensors are sufficiently robust that they are likely to
prove useful in control applications.
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