Numerical Analysis And Experimental Research For Choking Cavitator

Hydrodynamic cavitation had the advantages of high energyefficiency, large quantity of treatment, simple equipment, low costs ofmaintenance, easy realization for industrial applications. In recent yearsthe hydrodynamic cavitation was considered as a potential new watertreatment technology by the field. At present, it could not solve finely toincrease the volume ratio of the cavitation region to the water body andmake bubbles collapse effectively in the hydrodynamic cavitation device,resulting in cavitation effect of hydrodynamic cavitation unable to meetthe needs of the industrial applications of wastewater treatment. In orderto improve the cavitation effect of the hydrodynamic cavitation device, ithas importantly academic value and practical significance to seek a newmethod of treatment of industrial wastewater.Combination with the theory of hydrodynamic cavitation and theprinciple of gas-liquid two-phase critical flow, the research work studiedthe cavitation effects of chocking cavitator. Seven kinds of diameters ofchoke pipe of choking-cavitator under the different back-pressure weresimulated by the computational fluid dynamics software of FLUENT andcarried on cavitation noise signal test, the law of cavitation effects ofchocking cavitator impacted by the diameter of choke pipe and theback-pressure were researched. The results showed that the chokingcavitator having seven diameters of choke pipe would appear chokingflow phenomena when the back-pressure was less than or equal to thevalue of the critical pressure. The varied characteristic-parameters in thechoked section upstream on the axis of choke pipe such as pressure,volume fraction of air, Mach number, were not affected by the backpressure. When the homogenous gas-liquid two-phase flow was formedin the choke pipe, it was found that the Mach number of the gas-liquidtwo-phase flow increased gradually from the middle section to thechoking section of the choke pipe, and it would reach the maximum valueof0.98, very close to1, at the maximum pressure gradient. Increasing thechoke pipe diameter or back-pressure under the choked flow conditions, the maximum pressure gradient also increased and the choking sectionmoved to the choke pipe upstream. It had the best range of back-pressureto produce strong choking cavitation in the different diameters of chokepipe of choking cavitator. As the diameter of choke pipe increased thebest range of back pressure gradually reduced. The influence of cavitationeffects of chocking cavitator is small when the choke pipe diameter andback pressure change were changed within the best back pressure.The chocking cavitator would appear choking cavitation flow underthe suitable operating parameters. It could simultaneously satisfy thedifferent pressure request of the inception, growth and collapse of bubblein cavitation process, and enhance effectively the cavitation effect ofhydrodynamic cavitation device, which laid the technology foundationsfor the industrial application of wastewater treatment.