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ABSTRACT
Liquid rheology affects the separation performance of hydrocyclones. Sewage entering a de-foulant hydrocyclone with a reflux ejector (DFHRE) exhibits different rheological properties based on the source. In this study, particle image velocimetry is used to investigate the effect of liquid rheology on the overflow–suck–underflow effect of the DFHRE. Results show that the effects of the rheological properties, liquid concentration, and inlet velocity on the flow field are primarily reflected inside the locus of the zero vertical velocity at the cone section of the DFHRE. In addition, the overflow–suck–underflow effect becomes less prominent as the apparent viscosity increases. An increase in glycerin (Newtonian) concentration increases the total pressure drop, unlike an increase in polyacrylamide aqueous solution (PAM, non-Newtonian). Increasing the inlet velocity can enhance the overflow–suck–underflow effect in PAM owing to the lower drag force. This implies that the DFHRE can achieve an overflow–suck–underflow effect on fluids with a lower drag force and enhance the separation performance.
Graphical abstract
Highlights
Four Newtonian and non-Newtonian flow fields are tested in DFHRE via PIV.
Overflow-suck-underflow property is associated with drag force of fluid.
Change in split ratio with viscosity is different from the traditional hydrocyclone.
Apparent viscosity does not characterize total pressure drop in DFHRE.
Increasing glycerin viscosity can increase drag force but decrease suction.
Acknowledgements
This work was supported by the National Natural Science Foundation of China (No. 51978200). Thanks to Dr. Jinyi Tian from East China University of Science and Technology for long-term cooperation and valuable discussion.
Disclosure statement
No potential conflict of interest was reported by the author(s).