Insights into the weep performance and modeling of perforated plates

Weeping is an important hydraulic parameter for the design and optimization of perforated plates because it determines the lower limit of the tray operation (vapor load). Therefore, an accurate prediction of the weep rate is very important. First, according to our theoretical analysis of the weeping phenomena of large-scale perforated trays, we proposed three weep modes on a perforated tray: (1) random weeping in the bubbling zone, (2) dumping in the nonbubbling zone, and (3) liquid fluctuation-induced weeping. Second, a weep rate model was developed, and the literature data were correlated to determine model parameters. Results showed the fractional hole area substantially affects the model parameters. We also examined the effects of the tray structure, flow parameter, and fluid physical properties on the weep rate. Finally, the developed model was used to predict the weep rate of different scale trays reported in references, and the prediction results showed good agreements.