| Recently, more and more international researches focus on process intensification and design lots of new type reactors. Among them, Confined impinging jets reactors (CIJR) could offer high transfer performance and mixing efficiency, which is widely used in combustion, drying, grind and nanoparticles precipitation. However, the study of flow characteristics in CIJR is not sufficient. In this work, flow characteristics in equal jets (3-3mm) and unequal jets (3-4mm) were investigated at different inlet flow rates ranging from Re=21230to36951. Particle image velocimetry (PIV) and large eddy simulation (LES) were employed to measure and simulate the instantaneous to obtain flow patterns, mean velocity, stagnation and turbulence kinetic energy (TKE). By compared simulation with experiment, the accuracy of LES was verified. Turbulent kinetic energy (κ) distributions were obtained from two velocity components using isotropic approximation and a full calculation from all three velocity components. The result showed that the error between two calculation methods is40%at max. Turbulence anisotropy analysis using Lumley-Newman triangle method showed that the impinging area and the edge of jet were significant anisotropy. Stagnation offset in3-4mm unequal CUR was discussed by using LES. Compared to equal CUR, unequal CUR could be operated more flexibly.15%of flow rate fluctuation can still guarantee that two jets impinging in reactor chamber. L, the space above reactor axis, affects flow field very less. However, the stagnation moves to the side of small diameter as the L decreases. |
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