Open Balance Point and Dry Pressure Drop of a Rectangular Float Valve Tray: Experiment and CFD Simulation

The open balance point (OBP) is the critical gas load at which the float valve tray transitions into or out of the all-open state, playing essential roles in pressure drop characteristics and engineering design. Its prediction is a typical fluid–solid interaction problem. A rectangular float valve tray's Φ796 mm cold-model experiments demonstrated dry pressure drop and OBP differences between different gas-load-adjusting conditions (ascending or descending), leading to subsequent scaled-down experiments and numerical simulations. For the first time, the valve tray's OBPs were predicted by numerical simulations, using the lattice Boltzmann method. The wall and adjacent valve effects positively influenced the opening of the valves, dry pressure drop, and vorticity above the tray deck. This study indicated that in multivalve systems, the valve with the highest partial gas load falls first as the gas load descends from the all-open state. Moreover, the difference in the OBP between the gas-load-ascending or gas-load-descending conditions is attributed to the synergistic effects arising from the frictional resistance between the valve legs and tray orifices in the inclined stationary state, along with the gas-load competition among the valves in the multivalve systems.