A comprehensive modeling approach for intricate bearing flows within a rotary energy recovery device

Abstract

Energy recovery devices (ERDs), are increasingly adopted across various industries due to escalating global concerns regarding finite energy resources and associated environmental impacts. Pressure exchangers (PX), a common ERD, is an integral part of key industries like desalination and is increasingly prevalent in other energy-intensive industries like refrigeration. PXs play pivotal roles in reducing energy consumption by harnessing waste hydraulic energy within working cycles. The efficiency and recoverable energy in PXs are significantly influenced by internal leakages. While leakage is well-understood in individual bearings and mechanical seals, leakage within PXs remains a complex phenomenon due to the interdependency of multiple axial and radial leakage flows. Aligned with UN SDG 7 (Affordable and Clean Energy), PXs enhance the efficiency of critical technologies, resulting in lower energy consumption, improved system performance, and a reduction in GHG emissions. This reduction in emissions also plays a key role in supporting SDG 13 (Climate Action). Therefore, optimizing PX efficiency and minimizing losses are essential to maximizing their impact. This article provides a comprehensive modeling approach to analyze leakages and properties variation within bearings in PXs. Furthermore, a global optimization search methodology was developed to capture the interconnected nature of leakages and properties at the leakages intersection zones. Models for both radial and annular leakages within PXs were developed to analyze flow rates and variation of properties within bearings. These models avoid idealized assumptions and are based on real fluids. Models’ predictions for properties variation within bearings and pressures within leakage intersection zones were found to be in a good agreement with CFD and experimental validation.