Multiphase Transport With Conventional and Newly Designed Twin Screw Pumps in a Pipeline Network

Twin screw pumps are displacement pumps, working with two axially parallel and countercurrently rotating screws. They are experimentally and theoretically investigated by variation of the boundary conditions at the suction and discharge side of the pump. These are defined by the multi-phase flow patterns in the pipeline system of the closed loop test facility which is operated with oil, gas and water. Because of the efficient continuously operated phase separation, the plant is suited for the experimental investigation of the delivery characteristics in dependence of different flow patterns as well as modifications of the pump construction. A newly designed pair of screws (fig.1) with declining pitch is proposed for operation. The delivery of the pump depends on the declining volumes of the chambers, formed by the intermeshing screws moving from the suction to the discharge side. The improved performance of gas compression gives advantages in the efficiency of power consumption especially for multiphase pumping of mixtures with increasing gas volume flow fractions. By comparison with non-declining screws, the isothermal efficiency for declining screws is increased.