Simulation and optimization of a conical type swirl-vane separator in nuclear SG

Abstract

Swirl-vane separator is used as primary separator in nuclear SG for liquid droplet separation from steam flow. In order to improve the separator performance, in present paper, based on the commercial CFD software STARCCM+ and Euler-Euler two-fluid model, three-dimensional simulation and optimization of a conical swirl-vane separator are performed to study the flow filed and separation performance of this new designed separator. According to the results, a low-pressure and low-velocity wake region is formed at the swirler outlet and its shape narrows first and then enlarges along the flow direction due to the reduced flow channel of the conical barrel. The steam axial velocity exhibits a “M” type distribution while the tangential velocity displays a “V” type distribution in the radial direction. The steam radial velocity is about an order lower than the other two velocity components. The static pressure decreases sharply in the swirler, demiser and diffuser part, which is the main energy loss in the separator. On the whole, the structure of conical barrel and drain holes are very important for liquid separation. Within a certain range, a smaller hole diameter, a larger axial location of drain holes and a smaller conical angle can improve the separation efficiency of the swirl vanes, but also increases the pressure loss of the conical barrel section.