Study on two-phase swirling flows in a gas-liquid separator with three pick-off rings

Experiments on air-water two-phase swirling flows in a one-fifth scale model of a steam separator with three pick-off rings (PORs) are carried out to investigate characteristics of two-phase swirling flows and separator performance. In addition to flow observation, liquid film thickness, flow rates of separated liquid and pressure drops are measured. The ranges of the gas and liquid volume fluxes, JG and JL, tested are 12.0 ⩽ JG ⩽ 17.8 m/s and 0.05 ⩽ JL ⩽ 0.11 m/s, respectively. The main conclusions obtained are as follows: (1) the liquid film thicknesses at the PORs are smaller than the gap widths of the PORs under the nominal operating condition, which results in a high liquid-separation rate, (2) the increase in JG decreases the flow rate of unseparated liquid, whereas the flow rate of unseparated liquid is independent of JL except for low JG conditions, under which the liquid film thicknesses at the 2nd and 3rd PORs tend to be larger than the gap widths of PORs, (3) the presence of the 2nd and 3rd PORs realizes high liquid-separation rates by capturing the liquid unseparated at the 1st POR and the pressure drops at the 2nd and 3rd PORs are much smaller than that at the 1st POR, and (4) the pressure drops at the swirler and the 1st POR, which are the main source of the pressure drop of the separator under the nominal operating condition, increase with JG, whereas JL increases only the latter.