High-resolution two-dimensional particle image velocimetry(PIV)has been used to study the flow field formed by a disc impeller with a stirring Reynolds number Re=1 300 in a square stirred tank with a side length L of 220 mm,and the high-resolution flow field at the Kolmogorov scale was obtained.Based on the flow field data and the isotropic assumption,the turbulent kinetic energy distribution was obtained.The turbulent kinetic energy dissi-pation rates calculated by the direct definition method and the large eddy PIV method were compared.The results show that when the off-bottom height C=0.15L,the flow pattern of the disc impeller presents a unique single-cycle flow pattern,and the main vortex of the fluid is a single vortex structure.The maximum value of the turbulent kinetic energy in the stirred tank appears at the end of the blade discharge flow.At the Kolmogorov spatial analyti-cal scale,the turbulent kinetic energy dissipation rate calculated by the direct definition method is larger than that calculated by the large eddy PIV method,and the peak values of the turbulent kinetic energy dissipation rate are located at the blade end and the discharge flow region.The results of direct numerical simulation verify that the iso-tropic assumptions used in these two calculation methods are reasonable.
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