A Choking Cavitation Method and Equipment for Degrading Pollutants in Wastewater

Document Type : Regular Article


1 School of Mechanical Engineering, Hunan University of Science and Technology, Xiangtan, 411201, China

2 School of Business, Hunan University of Science and Technology, Xiangtan 411201

3 School of mechanical engineering, Hunan University of Science and Technology, Xiangtan, 411201

4 School of Mechanical Engineering, Hunan University of Technology, Zhuzhou 412007


A cavitator, with a structure of an annular conical aperture, a throat and a collapse cavity, was proposed to form a choking cavitation flow for pollutants degradation in wastewater treatment. Experiment was conducted in this new cavitator to investigate its flow characteristics and pollutant degradation ratio by employing Mythylene blue (MB) as a pollutant in pure water. It was found that choking cavitation flow appears in the throat by controlling the pump pressure and liquid flow rate in a rule. The pollutant degradation ratio in choking cavitation flow is much larger than that in normal cavitation flow, because plenty of cavitation vapours are born, grow up, and finally collapse in this cavitator in the choking cavitation condition. Gemetrical parameters also affect pollutant degradation ratio, and the optimal gemetrical parameters for this proposed cavitator are suggested.


Akmandor, I. S. and T. Nagashima (2015). Predictions for cryogenic homogeneous two-phase flows in a choked laval nozzle. Journal of Thermophysics and Heat Transfer 13, 355-363.##
Badmus, K. O., J. O. Tijani, E. Massima and L. Petrik (2018). Treatment of persistent organic pollutants in wastewater using hydrodynamic cavitation in synergy with advanced oxidation process. Environmental Science and Pollution Research 25, 7299-7314.##
Didenko, Y. T., W. B. Mcnamara and K. S. Suslick (1999). Hot spot conditions during cavitation in water. Journal of the American Chemical Society 121, 5817-5818.##
Griebe, R. W., R. J. Schoenhals and E. Winter (1970). Choking and shock phenomena in a single component two-phase flow including vibrational effects. Wärme - und Stoffübertragung 3, 7-18.##
Langone, M., R. Ferrentino and G. Trombino (2015). Application of a novel hydrodynamic cavitation system in wastewater treatment plants. UPB Scientific Bulletin, Series D: Mechanical Engineering 77, 225-234##
Li, D., Y. Kang and X. L. Ding (2017). Experimental study on the effects of feeding pipe diameter on the cavitation erosion performance of self-resonating cavitating waterjet. Experimental Thermal and Fluid Science 82, 314-325.##
Li, D., Y. Kang and X. L. Ding (2016). Effects of area discontinuity at nozzle inlet on the characteristics of high-speed self-excited oscillation pulsed waterjets. Experimental Thermal and Fluid Science 79, 254-265.##
Li, D., Y. Kang and X. L. Ding (2016). Effects of nozzle inner surface roughness on the cavitation erosion characteristics of high-speed submerged jets. Experimental Thermal and Fluid Science 74, 444-452.##
Liu, W. C., Y. Kang and M. X. Zhang (2017). Self-sustained oscillation and cavitation characteristics of a jet in a Helmholtz resonator. International Journal of Heat and Fluid Flow 68, 158-172.##
Lohani, U. C., K. Muthukumarappan and G. H. Meleharayil (2016). Application of hydrodynamic cavitation to improve antioxidant activity in sorghum flour and apple pomace. Food and Bioproducts Processing 100, 335-343.##
Mancuso, G., M. Langone and G. Andreottola (2016). A swirling jet-induced cavitation to increase activated sludge solubilisation and aerobic sludge biodegradability. Ultrasonics Sonochemistry 35,489-501.##
Nilpueng, K. and S. Wongwises (2011). Choked flow mechanism of HFC-134a flowing through short-tube orifices. Experimental Thermal and Fluid Science 35, 347-354.##
Pawar, S. K., A. V. Mahulkar and A. B. Pandi (2017). Sonochemical effect induced by hydrodynamic cavitation: Comparison of venturi/orifice flow geometries. AICHE Journal 63, 4705-4716.##
Patil, P. N., S. D. Bote and P. R. Gogate (2014). Degradation of imidacloprid using combined advanced oxidation processes based on hydrodynamic cavitation. Ultrasonics Sonochemistry 21, 1770-1777.##
Rajoriya, S., S. Bargole and V. K. Saharan (2017). Degradation of a cationic dye (Rhodamine 6G) using hydrodynamic cavitation coupled with other oxidative agents: Reaction mechanism and pathway. Ultrasonics Sonochemistry 34, 183-194.##
Rouse, H. and A. H., Abul-fetouh (1950). Characteristics of irrotational flow through axially symmetric orifices. Journal of Applied Mechanics- Transactions of the ASME 17, 421-423.##
Sarc, A., T. Stepisnikperdih and M. Petkovsek (2017). The issue of cavitation number value in studies of water treatment by hydrodynamic cavitation. Ultrasonics Sonochemistry 34, 51-59.##
Sivakumar, M. and A. B. Pandit (2002). Wastewater treatment: A novel energy efficient hydrodynamic cavitational technique. Ultrasonics Sonochemistry 9, 123-131.##
Tao, Y. Q., J. Cai and X. Huai (2017). A novel device for hazardous substances degradation based on double-cavitating-jets impingement: Parameters optimization and efficiency assessment. Journal of Hazardous Materials 335, 188-196.##
Trapp, J. A. and V. H. Ransom (1982). A choked-flow calculation criterion for nonhomogeneous, nonequilibrium, two-phase flows. International Journal of Multiphase Flow 8, 669-681.##
Vichare, N. P., P. R. Gogate and A. B. Pandit (2000). Optimization of Hydrodynamic Cavitation Using a Model Reaction. Chemical Engineering and Technology 23, 683-690.##
Wang, X., J. Wang and P. Guo (2008). Chemical effect of swirling jet-induced cavitation: degradation of rhodamine B in aqueous solution. Ultrasonics Sonochemistry 15,357-363.##
Zhang, F. H., H. F. Liu and J. C. Xu (2013). Experimental investigation on noise of cavitation nozzle and its chaotic behaviour. Chinese Journal of Mechanical Engineering 26, 758-762.##