Comparative on Flow Field Characteristics of Cavitation Jet Nozzles with Different Structures
The type and structure of a nozzle are the key factors affecting the performance of cavitation jet.In the paper,first,the CFD numerical simulation method was used to explore the flow field characteristics of organ-pipe self-oscillation cavitation jet nozzle,Helmholtz cavitation jet nozzle,angular cavitation jet nozzle,central-body cavitation jet nozzle and impeller-type rotating cavitation jet nozzle.Second,the laboratory test of the jet noz-zle flow field was carried out,and the reliability of the numerical analysis was verified by taking the jet diffusion angle as the evaluation index.Finally,based on the flow field characteristics and field engineering application re-quirements of cavitation jet nozzles with different structures,the types of cavitation jet nozzles suitable for different scenarios were recommended and explained.The study results show that the organ-pipe self-oscillation cavitation jet nozzle has strong jet impact pressure and high stability(the highest impact pressure is 12.165 MPa),and is suit-able for the auxiliary rock breaking scenario in the drilling process.The Helmholtz cavitation jet nozzle has a high pulse frequency(2.0 kHz)and a long cavitation bubble migration distance,and is suitable for the flushing and blockage removal scenario of old wells.The angular cavitation jet nozzle has strong jet diffusibility and high cavitati-on degree,and is suitable for the demulsification scenario of emulsified oil in oilfield wastewater treatment.The center-body cavitation jet nozzle has a cavitation bubble group concentrated at the outlet center and a jet impact pressure of 7.047 MPa,and is suitable for coal seam gas desorption and seepage scenario in coalbed methane ex-ploitation.The impeller-type rotating cavitation jet nozzle has an inverted"U"-shaped velocity distribution and a large cavitation range,and is suitable for the radial branch drilling scenario in natural gas hydrate exploitation.The study results provide a theoretical basis for the selection of cavitation jet nozzles.
cavitation jetjet nozzleflow field characteristicsnozzle selectionjet diffusion angle
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