Simulation on the influence of inlet velocity and solid separation gap on the separation characteristics of a separating device for three phases: Oil, water and solid

Abstract

Water and solid particles, such as wear particles and sand, will enter lubricating oil during the operation of machinery, seriously affecting the performance and lifetime of the oil, and adversely affecting the machinery. Therefore, a device for simultaneously extracting water and solid particles mixed with lubricating oil is proposed. For such a device, a numerical model is established by combining mixture, Reynolds-stress, population-balance, and discrete-phase models to investigate the influence of inlet velocity and solid separation gap on separation characteristics, and the three-phase separation experiment is carried out. Results show that the oil-water-solid phase separating device delivers an excellent performance, and that the dewatering, deoiling, and solid particle recovery rates reach 76.9 %, 88.55 %, and 88.97 %, respectively; and separation time of solid particles and droplets and the tangential velocity increases with the increase of the solid separation gap. Furthermore, at an inlet velocity of 9 m/s, a large tangential velocity is generated to provide a strong centrifugal force while maintaining the stability of the internal flow field. This work provides a valuable guide for the design of high-performance devices for lubricating oil purification using physical methods.