Study of the effect of turbulent mixing on chemical reaction in liquid

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In order to clarify the effect of turbulent mixing on the chemical reaction occurring in liquid, the researches were performed both experimentally and computationally. Chemical reaction, simple but suited to optical measurement and selected is the type; A + B * R,B + R * S (the azo coupling of 1-naphthol (A) with diazotised sulfanilic acid (B) in dilute, aqueous, alkaline buffered solution). The optical fiber probe with the core diameter of 10 mum has been anew developed to measure the instantaneous concentrations of chemical products (R and S) at a spatial point. The improved concentration measuring system of multiple species was also fitted up. As the fundamental research,the turbulent jet of species B into species A was investigated. At first, the mean velocity and velocity fluctuation rms profiles were measured using the fiber type of LDV system purchased. Next, various statistical properties of the concentration fields of chemical products R and S (the mean value, fluctuation rms … More value, correlation between R and S, pdf, etc.) were investigated in detail.As the research on the mixing process in the turbulent pipe flow, the diffusion field of single species from the continuous point source on the wall was measured. The turbulence in the pipe (Inner diameter D=100 mm, the length of the test section 2000 mm, Reynolds number Re=U<@D2m@>D2D/nu (] SY.simeq.[) 20000, U<@D2m@>D2: maximum mean velocity) was not fully developed but the radial profile of the mean velocity is almost self-similar in the downstream direction. By examining the contours of the iso-mean concentration and iso-concentration fluctuation rms values, the spread of the plume was also clarified.With regards to the numerical simulation, the diffusion of fluid particle around a circular cylinder was investigated by the combined model of random Fourier modes and random flight. The molecular mixing models of the passive scalar in turbulent flow were also examined by the PDF method. To compare these numerical results with experiments, the disturbance effect of a sphere on the plume developed in grid-turbulence was investigated experimentally. From the fractal analysis, it is elucidated that the flow distortion due to the sphere is not effective to the change of the fractal dimension. The mixing process of two species in the case of coaxial jet was also examined. Less