CFD gas–liquid simulation of oriented valve tray

Computational fluid dynamics (CFD) has recently emerged as an effective tool for the investigation of the hydraulic parameters and efficiency of tray towers. The computation domain was established for two types of oriented valves within a tray and meshed into two parts with different grid types and sizes. The volume fraction correlation concerning inter-phase momentum transfer source was fitted based on experimental data, and built in UDF for simulation. The flow pattern of oriented valve tray under different operating conditions was simulated under Eulerian–Eulerian framework with realizable k-ε model. The predicted liquid height from CFD simulation was in good agreement with the results of pressure drop and volume fraction correlations. Meanwhile, the velocity distribution and volume fraction of the two phases were demonstrated and analyzed, which are useful in design and analysis of the column trays.

At the part close to deck, liquid as a continuous phase domain the flow pattern. Near the bottom of the tray, the liquid was drawn toward the center and was dragged up vertically by gas, but close to the weir, the velocity of liquid was up-inclined due to restraint of the weir. This was because the lower liquid under valve height (15 mm) was more drastic, delivering momentum to upper liquid and the gas from the valves directly up-threw liquid which influenced the liquid direction largely. The liquid disengaged itself from the dispersed gas phase and traveled down the sides, resulting in circulation near liquid inlet. Due to gravity, water has the downward velocity in upper area, and at the same area, gas has the upward velocity.Figure optionsDownload as PowerPoint slide