Improvement of separator performance with modified pick-off ring and swirler

The swirler and the 1st pick-off ring (POR) of a gas-liquid separator are improved to reduce the pressure drop, ΔPT, in the separator while keeping the flow rate of separated liquid, WST, high. Two swirler designs are presented, i.e. V8 (swirler with eight vanes) and V6 (swirler with six vanes), whose diameters of the hubs supporting the vanes are smaller than that of the normal swirler, N8, and the nose shape of vanes are coned. The swirlers are installed into a one-fifth scale separator with three PORs. The gap width of the 1st POR is reduced to the value of the liquid film thickness in the barrel of the separator and the rear shape of the 1st POR is smoothed. The performance of the downscaled separator with the proposed swirlers and the 1st POR are evaluated under the nominal operating condition of the Hyper BWR and a higher quality condition. As a result, the following conclusions are obtained in the present experimental range: (1) ΔPT in the separator is reduced by 23% using V8, and V8 gives the same WST as N8, confirming that the decrease in the hub diameter and the coned-nose shape of vanes are effective, (2) V6 can realize further reduction of ΔPT (38%) without deteriorating the liquid-separation rate, (3) the reduced gap width of the 1st POR and a tapered shape of the downstream side of the 1st POR are also effective to decrease the pressure drop, i.e. the improved POR decreases ΔPT by 42% and 54% by combining with V8 and V6, respectively, and (4) the improved separators also show good performances in ΔPT and WST at the higher quality condition.