Simultaneous temperature, concentration, and velocity fields measurements in a turbulent heated jet using combined laser-induced fluorescence and PIV

摘要

Mixing process of a passive scalar in a heated turbulent jt at Reynolds numbers between 13,000 and 21,000 is studied experientaly using combined two-color Planar Laser-Induced Fluorescence (2λ-PLIF) and Particle-Image Velocimetry (PIV). The PLIF system is based on acetone fluorescence for temperature and concentration measurement. The aim of the present paper is to obtain a reliable reference data set for the validation of numerical simulation of turbulent fluxes. Experiment was carried out on a heated turbulent jet of acetone-seeded air emanating from the 10 mm-diameter nozzle exit of an electric air heater with exit temperature T_i = 500 K. The jet is seeded to approximately 3% acetone by bubbling the air stream through liquid acetone. The mean and fluctuating dynamic and thermal fields are investigated and determined. This tool will allow to determine the temperature-velocity as well as the concentration-velocity cross-correlations in order to characterize the turbulent characteristics of the flow such as the turbulent diffusivity and the turbulent Prandtl number.