4. Conclusions

A new experimental device is produced, and the hydrodynamics of the blade unit of the tridimensional rotational flow sieve tray are experimentally studied. The flow pattern of the unit under different operating conditions is visually analyzed using the image processing method. The differential pressure pulsation signals under different flow patterns of the blade unit are studied in the time and frequency domain, and the operating domain of the blade unit is clarified. Finally, the distribution of the rotational and perforated flow for the gas-liquid phase, which flows through the blade unit, is measured and analyzed. The following conclusions are obtained.
1) The overflow and spray distributions for the liquid phase are produced according to the liquid phase arrangement methods. Three flow patterns are defined under overflow distribution. They are BFF, CPF, and DMF. Two patterns are defined under spray distribution. They are FJF and JMF.
2) The time and frequency domain analysis for the differential pressure pulsation signals corresponding to each flow pattern is carried out. In the time domain, the increase in the kinetic energy factor of the gas phase will increase the amplitude of the differential pressure signal. When the interaction of the gas-liquid is stronger, the fluctuation of the differential pressure signal is larger. In the frequency domain under the overflow distribution, the perforation and gas-liquid interaction intensity changes the values of the main frequencies, and the variation range is (2.44 Hz–5.4 Hz). Moreover, when the perforation intensity of the gas phase is higher, the PSD value of the main frequency is higher. The PSD values are affected by the gas-liquid mixing strength, when the liquid arrangement method is the spray distribution. The influence of the airflow on the perforation intensity is weak, and the variations of the main frequency are stable. Finally, the operating range of each flow pattern under the two distribution modes is clarified, according to the changes in the time and frequency domain of the signal, as well as the results of the image observations when the flow pattern changes.
3) A rotational flow ratio is introduced to investigate the distributions of the rotational-perforated flow for the gas-liquid phase. In the experimental operating domain, the gas-phase rotational flow ratio is greater than 0.6, and the liquid-phase is less than 0.5. The gas phase through the blade unit is dominated by the rotational flow, while the liquid phase is perforated flow. The changes in the rotational flow ratio for the gas phase under different liquid arrangement methods are similar. The rotational flow ratio for the gas phase has a turning point when the liquid film is broken by the airflow. The turning point isF s = 1.6 (m/s*(kg/m3)0.5) (when the arrangement method is overflow distribution: L W = 26 m3/(m2*h),F s = 2.0 (m/s*(kg/m3)0.5)). Under the overflow distribution, the sieve holes of the blade unit have a limit in the flux for the liquid phase, and the spray density corresponding to the limit will be affected by the gas phase. Finally, a prediction model for the rotational flow ratio under two liquid arrangement methods is proposed, and the error is within 10%.