A new type of composite tridimensional rotational flow sieve tray is proposed. The flow pattern and operation domain of the tray were defined and divided by the image shooting method, combined with the standard deviation of the pressure difference sequence. There are membrane--drip column and foam--embolic flow in the TRST area of the internal packing--type tray, while bubbly and milk froth-ribbon flow are present in the packing area of the external packing-type tray. This study focused on the influence of the tray structure parameters on the pressure drop. Under the experimental operating conditions, the dry pressure drop was within 160 Pa, while the wet pressure drop was within 900 Pa. Under the same structural parameters, the internal packing--type pressure drop of the tray was higher than that of the external packing-type tray. A mathematical model of the pressure drop between dry and wet trays was established.

The blade unit of a tridimensional rotational flow sieve tray (TRST) is the origin for the rotational–perforated flow. The flow field of that was investigated using the Multi-fluid VOF method. The water fractions, and the gas perforation velocity on the blade unit were investigated. The liquid phase distribution in the jet and mixed flow is more dispersed than that in film and jet flow. The gas–liquid two-phase velocity fluctuated with the radial distance. The rotational and perforated flows on the blade unit were analyzed separately by the local rotational flow ratio . The variation range of the ratio for the gas-phase was 0.6 – 0.85, and that for the liquid-phase is 0.2 – 0.8. Based on the Q criterion, the vortices were mainly concentrated near the sieve holes. The simulation provides an important theoretical basis for the mass transfer investigation and structural optimization of the blade unit.

The flow characteristics of the blade unit of a tridimensional rotational flow sieve tray was investigated experimentally in this study. First, the flow patterns are defined under different liquid arrangement methods. They are bilateral film flow, continuous perforated flow, and dispersion-mixing flow in overflow distribution and film and jet flow and jet and mixed flow in spray distribution. Second, the time and frequency domain analysis of the differential pressure pulsation signal in the blade unit is carried out. The influence of perforation and mixing intensity on the flow pattern transition is clarified. Third, the rotational flow ratio of the gas-liquid phase is measured. The influence of the operating conditions on the distribution of the rotational and perforated flow for the gas-liquid phase is investigated. Finally, a prediction model for the rotational flow ratio is proposed. The prediction results agree well with the experimental data.