Experimental characterization of turbulent mixing performance using simultaneous stereoscopic particle image velocimetry and planar laser-induced fluorescence

• Published in: Experiments in fluids 2019-02, Vol.60 (2), p.1-13, Article 28
• Main Authors: Hitimana, Emmanuel, Fox, Rodney O., Hill, James C., Olsen, Michael G.
• Format: Article
• Language: English
• Subjects: Computational fluid dynamics; Concentration gradient; Diffusivity; Engineering; Engineering Fluid Dynamics; Engineering Thermodynamics; Fluid- and Aerodynamics; Fluxes; Heat and Mass Transfer; Low turbulence; Particle image velocimetry; Planar laser induced fluorescence; Research Article; Schmidt number; Shear stress; Stereoscopy; Turbulence intensity; Turbulent flow; Turbulent mixing; Velocity distribution; Velocity measurement; Viscosity; Vortices
• ISSN: 0723-4864; 1432-1114
• DOI: 10.1007/s00348-018-2669-y

Simultaneous measurements of velocity and concentration using stereoscopic particle image velocimetry (stereo-PIV) and planar laser-induced fluorescence (PLIF) were used to investigate the mixing performance of a scaled-up multi-inlet vortex reactor (MIVR). Data were collected in three measurement planes located at different heights from the reactor bottom (¼, ½, and ¾ of the reactor height) for Reynolds numbers of 3250 and 8125 based on the reactor inlet velocity and hydraulic diameter. The collected data were analyzed to determine turbulent flow statistics such as turbulent viscosity, turbulent diffusivity, and turbulent Schmidt number. When analyzed across 16 different azimuth angles and radial positions ( r ) normalized by the reactor radius (Ro), the turbulent viscosity was found to be nearly axisymmetric. In the free-vortex region ( r /Ro > 0.2), the turbulent viscosity results were nearly constant. Near the center of the reactor in the forced-vortex region ( r /Ro