Development of a a new temporal method of phosphorescence of ZnO particules applied to temperature measurments in water.

In numerous experimental studies, it is necessary to measure instantaneous temperature in laminar or turbulent water flow in order to study mixing or heat transfer between anisothermal flow and a wall for instance.

These experimental measurements are necessary to validate developments of new turbulence models or to validate L.E.S simulations for instance in case of high turbulent flow. instantaneous 2D fields of temperature can be obtained non intrusive metrology from images issued from Fluorescence or Phosphorescence emission consecutive to Laser / particule interactions. Two kind of techniques can be used: spectral integration of total or filtered wavelengthes method, called spectral methods and time resolved emission method.

This study deals with experimental development of a novel technique issued from temporal emission of ZnO phosphorescence by using two cameras synchronized with 266 nm UV LASER. Experimental setup is proposed and calibration curve with Temperature sensibility is studied in the field of 20 - 35 °C in a in house calibration cell.

Another 2D instantaneous temperature fields metrologies are applied like classical spectral ZnO phosphorescence emission and B Rhodamine fluorescence emission. All of these techniques are using 266 nm Laser emission and visible light intensified camera.

A comparison of thesensibility and precision of these 3 techniques are then proposed and discussed to show that temporal method apply to ZnO phosphorescence with 2 cameras show a better sensitity of temperature measurment.