| It has long been recognized that the flow pattern, especially the velocity distribution of the fluid, is of great importance in determining the performance of the equipment which using structured packing as their internals. But detailed local information on the hydrodynamics of structured packed columns is rather scarce in literature.By using three-dimensional laser Doppler velocimetry (LDV), the liquid velocity distribution of the glycerol aqueous solution was measured in a typical unit of structured packing (Mellapak350Y). Time averaged three-dimensional velocity distributions of the unit were measured at different flow rates. The experimental data showed that the liquid velocity profile of the single phase flow is complex because of the special geometry of the unit of structured packing. In the centre region of the unit, the liquid was mixed and re-distributed. That was the cause generating the vortexes and secondary flow. The velocity distribution varied in different flow velocity.The turbulence energy was calculated and the turbulence energy distribution of the middle section was obtained. Compared with the velocity vector map, it was found that the higher turbulence was found in the centre vortex region and refluent regions at the bottom and top of the packing. To further understand the intrinsic features of turbulence in the structured packing, wavelet transform analysis was adopted. It is indicated by power distribution for varying wavelet scales that the fluid flow in structured packing is an anisotropic turbulence at all scales.This study shows that mapping and analyzing the flow field in the structured packing using the advanced experimental as well as data analysis techniques may indeed be possible. Studies in this direction would help in the design, optimization and operation of the structured packing columns. The methodology is therefore suitable for evaluating hydrodynamics and turbulent structures in structured packing.
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