1 Two - Color Particle Tracking Velocimetry and Thermometry

Particle Tracking Velocimetry (PTV) and Particle Image Velocimetry (PIV) originally have been established for velocity field visualization. In the meantime flow fields of interest in classical and applied fluid mechanics are essentially inseparable from thermal effects in the majority of cases. Different physical phenomena are involving for temperature field mapping depending on physical properties and data required by certain class of application, such as: Thermochromic Liquid Crystal (TLC) Digital Particle Image Velocimetry/Thermometry (DPIV/T), Planar Filtered Rayleigh Scattering (FRS) technique, Coherent anti-Stokes Raman Scattering (CARS) technique, micron-resolution particle image velocimetry (μ-PIV) for temperature measurement which based on the premise that Brownian motion will cause width-wise broadening of the cross-correlation peak, etc. Most of proposed techniques utilize different radiation sources for velocity and temperature respectively (except TLC), usually require sophisticated hardware, optical access to the interrogating flow from different directions and pretty complex calibration. In present work inherent or laser induced irradiation of individual tracer particles or distinguishable groups of molecules (injected into hot flow in the form of liquid evaporating droplets) is examined as information source of both temperature and velocity fields in an assumption of detectable relative light intensity from each tracer depending from its average temperature, similar to infrared (IR) pyrometry applied to each individual tracer within interrogation flow domain. This technique seems to be quite attractive alternative to more sophisticated aforementioned technologies for a number of particular applications most of all due to much less expensive implementation and simple calibration providing acceptable accuracy with sub-pixel spatial resolution as shown in figure 1 for an computer simulated and then recovered velocity and temperature distribution. Appropriate demonstrational experiments are carrying out. 160