Affiliations: Turbulent Mixing and Unsteady Aerodynamics Laboratory,
Department of Mechanical Engineering, A22, RCE Building, Michigan State
University, East Lansing, 48824, Michigan. U.S.A. E-mail:
[email protected]
Abstract: A unique method is described in the present paper for quantitative
mapping of temperature field in a liquid flow by taking advantage of the
phosphorescence lifetime dependence on temperature. This methodology represents
an extension of the Molecular Tagging Velocimetry (MTV) technique. As in MTV
measurements, the phosphorescence signal is imaged at two successive times
within the lifetime of the tracer. The phosphorescence lifetime, estimated from
the intensity ratio of the two images at each point, is calibrated with respect
to the temperature. This procedure eliminates the effects of the variation of
the incident illumination. The method described in the present paper also
allows the simultaneous quantification of velocity and temperature fields in a
fluid flow by using the same phosphorescent tracer
(1-BrNp·Gβ-CD·ROH) and the same optical and equipment setup.
While the displacements of the tagged regions between two interrogations
provide the estimate of fluid velocity vectors, the intensity ratio of the two
images represents the fluid temperature distribution. The implementation and
application of the new technique are demonstrated by conducting simultaneous
temperature and velocity measurements in a pulsed cold jet discharging into hot
ambient fluid.
Keywords: Temperature measurement, Molecular tagging velocimetry, Simultaneous velocity and temperature measurement, Phosphorescence lifetime measurement