CFD study on flow characteristics of sieve tray columns with circular downcomers

Abstract

To investigate the flow characteristics of sieve tray columns with circular downcomers, the Euler–Euler gas–liquid two‐phase flow model is used to simulate a three‐dimensional sieve tray column. Each phase is regarded as an interpenetrating continuum with independent transport equations. The velocity distribution, clear liquid height, and foam layer height are predicted by the model. The correlation is established for predicting the clear liquid height on the sieve tray. The results show the following: (1) The sensitivity of the clear liquid height to the gas phase load is greater than that of the liquid phase load. (2) When the gas–liquid distribution is stable, the flow on the round sieve tray column presents a piston flow pattern. (3) The average liquid holdup of the circular downcomer of the three heights all showed a slow decrease at first, and then an inflection point appeared near the height of 0.02 m, after which the liquid holdup dropped sharply. (4) The established correlation has good predictive performance for calculating the clear liquid height in the column, and the relative error between the calculated value and the actual value is less than 10%.