Research on the pressure and flow characteristics of seawater axial piston pump considering cavitation for reverse osmosis desalination system

Abstract

Seawater axial piston pump (SWAPP) has been widely used as the power component in the seawater reverse osmosis (SWRO) desalination systems, whose flow quality could result in significant influences on the performance of RO membranes and SWRO system. This thesis proposed an efficient fully parameterized mathematical approach for the flow and pressure characteristics of SWAPP that is modeled by lumped parameter techniques considering gaseous and vaporous cavitation simultaneously. To address the complex structure of the port plate in SWAPP, especially silencing groove, an innovative model based on the Monte Carlo method was originally proposed, and In-depth comparison with piecewise functions validated the accuracy, efficient and convenient of Monte Carlo approach for calculating the flow area of SWAPP. Particularly, the influence of shaft rotational speed and inlet pressure on the instantaneous discharge flow and pressure of SWAPP was comparatively studied. In addition, a SWRO desalination system was constructed to evaluate the effect of discharge pressure of SWAPP on the RO concentrated brine pressure. The results indicate that the presented model can precisely capture the instantaneous discharge pressure and flow of SWAPP. Besides, increasing the shaft rotational speed and inlet pressure are reliable solutions to enhance the flow performance of SWRO system.