Research progress on the influence of structural and operating parameters on the enhanced separation performance of mini-hydrocyclones

Mini-hydrocyclones, as a type of centrifugal separator, have smaller cut sizes and higher separation performance. With the rapid progress of industrialization, mini-hydrocyclones suitable for separating immiscible multiphase media have been widely used in key industries such as petroleum, chemical, mining and environmental protection. However, the influence of structural and operating parameters on the separation performance of minihydrocyclones is not yet clear. We hereby summarize the research progress on the structural parameters of minihydrocyclones in inlet, swirl chamber, conical section, overflow pipe, and operating conditions such as inlet flowrate and split ratio. We focus on summarizing the theoretical advancements and research achievements in improving the structural parameters of mini-hydrocyclones. For example, in order to achieve efficient separation for fine oil droplets, innovative structures such as coalescence-hydrocyclone separator, droplet size reconstruction hydrocyclone, positive rotation mini-hydrocyclone and reverse rotation mini-hydrocyclone have been designed. In addition, the impact of operating conditions on separation performance is analyzed and summarized, including characteristics of the flow field, pressure loss, cutsize, and separation efficiency. For example, the inlet flowrate and split ratio only affect the strength of the flow field, while have little influence on the flow field structure, LZVV(Locus of Zero Vertical Velocity) shape and secondary vorticity. At the same time, prospects were made for the theoretical mechanism, structural design innovation, and coupling enhancement of minihydrocyclones with other separation processes, to guide the enhancement and optimization design of minihydrocyclones in the separation process and thus assist in further improving separation efficiency.