Numerical Investigation of the Influence of a Splitter Plate on Mixing Transfer in the Ducts of a Rotary Energy Recovery Device

Abstract

The rotary energy recovery device (RERD) is integral in reducing energy consumption in desalination processes. The absence of a physical piston in RERD ducts allows salinity transfer from the brine to the seawater stream, which reduces RERD efficiency. To address this challenge, this study investigates the potential of utilizing splitter plates as a flow control technique to decrease the mixing degree within RERDs. Numerical simulations were performed to examine five different splitter plate configurations in RERD ducts in order to identify optimal designs for reducing the mixing degree. The analysis of internal streamlines and vortex distributions revealed that horizontal splitter plates positioned at the duct inlet effectively suppressed swirling flows, while splitter plates positioned at the center of the duct suppressed the formation of flow-induced vortices. This resulted in a more uniform salinity distribution and a reduction in the mass transfer rate between brine and seawater streams. The most significant reduction in the volumetric mixing rate was observed when employing cross-spread splitter plates positioned at the center of the duct. This paper presents an innovative method to reduce the mixing degree in the RERD.