![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
ABSTRACT
Influences of the vortex finder diameter and length on the performance of a 50 mm diameter hydrocyclone for particle separation were investigated comprehensively, and the grade efficiencies of particles as well as the cut-size were analyzed detailedly. The results indicated that the separation efficiency could be promoted by employing a vortex finder with a small diameter and appropriate length, and the optimum length highly depends on the vortex finder diameter. It is observed that the optimum length of the vortex finder increases first and then decreases with the increase of its diameter. Additionally, the grade efficiencies demonstrate that large particles (>25 μm) can be almost entirely separated when the vortex finder diameter is lower than 20 mm, and large particles will escape from the vortex finder if the vortex finder diameter is too large (i.e., 25 mm). Besides, the impacts of the vortex finder diameter and its length on the cut-size are negligible when a small diameter vortex finder (less than 20 mm) is employed, while the cut-size increases significantly when a large vortex finder is used. Finally, empirical correlations have been established to quantitatively predict the optimum vortex finder length, separation efficiency, and Euler number.
Nomenclature
| c | = | Solid concentration, kg/m3 |
| dc | = | Cylindrical section diameter, mm |
| do | = | Overflow pipe diameter, mm |
| dI | = | Hydraulic diameter of the rectangular inlet, mm |
| di | = | Particle size, mm |
| d50 | = | Cut-size, μm |
| dp,50 | = | Median particle size, μm |
| Eu | = | Euler number |
| f(di) | = | Particle mass percentage, % |
| fi | = | Predicted data |
| G(dj) | = | Grade efficiency, % |
| lc | = | Cylindrical section length, mm |
| lo | = | Vortex finder length, mm |
| m | = | Mass flow rate, kg/h |
| n | = | The number of data points |
| P | = | Pressure, kPa |
| Qi | = | Feed volume flow rate, m3/h |
| Re | = | Reynolds number |
| R2 | = | Regression coefficient |
| rd | = | Ratio of vortex finder diameter to cylindrical section diameter |
| rl | = | Ratio of vortex finder length to cylindrical section length |
| v | = | Inlet velocity, m/s |
| yi | = | Measured data |
| = | Average value of the measured data | |
| Greek letters | = | |
| η | = | Separation efficiency, % |
| μ | = | Viscosity, Pa·s |
| ρ | = | Fluid density, kg/m3 |
| Subscripts | = | |
| i | = | Inlet |
| o | = | Overflow outlet |
| u | = | Underflow outlet |
Acknowledgments
This work was supported by the National Natural Science Foundation of China (Nos. 21878318; 21808234), the DNL Cooperation Fund, CAS (DNL201902), “Transformational Technologies for Clean Energy and Demonstration”, Strategic Priority Research Program of the Chinese Academy of Sciences (CAS) (XDA21060400), Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) and Dalian National Laboratory for Clean Energy (DNL) of CAS (QIBEBT ZZBS201803; QIBEBT I201907), CAS Key Technology Talent Program, Project of CNPC-DICP Joint Research Center, and Director Innovation Fund of Synthetic Biology Technology Innovation Center of Shandong Province (sdsynbio-2020-ZH-02).
Declaration of Interest Statement
No conflict of interest was declared.