Flow and Mixing Characteristics in Counter-Type T-junction (Influence of Flow Ratio on Mixing Characteristics)

The effects of flow rate ratio on flow and mixing characteristics for turbulent flow in a countertype T-junction channel have been investigated experimentally. The T-junction was modeled by a mixing tee with square cross sections, in which the mixing channel was connected with the main and counter channels at right angles. Detail distributions of velocity and concentration after the flow merging have been measured using Particle Image Velocimetry (PIV) and Planer Laser Induced Fluorescence (PLIF). Mixing of two flows around X/D=2-5 is enhanced with increase of flow rate ratio, and the concentration fields of the region are largely related to the longitudinal vortices induced by the centrifugal forces. The distributions of the velocity fluctuation in the transverse direction are similar to those of concentration in the mixing layer just after the flow merging. Two-point correlations of velocity fluctuation around the mixing interface were compared with those of concentration fluctuation. These results show that the spatial pattern of concentration fluctuation connected with turbulent mixing is conveyed downstream with extension growth.