Research On The Technical Characteristic Of Cavitation Impinging Stream

In recent years, with the improvement of the level of science and technology, China’sindustrial develope rapidly, but the content of the biodegradable organic matter inindustrial waste water is also increasing.In wastewater treatment efficiency organicpollutants degradation rate, investment cost, running cost and other aspects, the existingwastewater treatment methods and processes is difficult to adapt to the increasingrequirements of environmental protection, so efficient and environmentally friendlywastewater degradation process and technical means become the hot and difficult area ofresearch in the area.The concept of " Cavitation-impinging stream " is put forward in thiscontext.Based on the theory of computational fluid mechanics, cavitation and impingingstream, through the establishment of Cavitation-impinging stream mathematical model, thenumerical simulation of the flow field within the reactor, the verification experiment aboutcoupling effect of cavitation-impinging stream and other research tools, the technicalcharacteristics of Cavitation-impinging stream were studied.Firstly, through the establishment of the mathematical model of cavitation-impingingstream, equations of particle trajectories, velocity function and pressure function wereobtained then providing a theoretical basis to the cavitation impact characteristics of theflow field.Then aim to the created reactor model, numerical simulation of the velocity fieldand pressure field inside the reactor is conducted, the results of simulation are basicallysame with the variation rule of speed function and pressure function resulted bymathematical model.Through the research of the flow field of cavitation-impinging stream,it can be found that a certain vortex can be formed in the impact area, and the strongturbulence and pressure fluctuations will present entire flow field, and formate negativepressure zone;Accompanied by cavitation impact, instantaneous micro-jets, shock waveare generated, which contain a better role in promoting the mixing between the reactants,interphase heat and mass transfer.In order to verify that cavitation-impinging streamtechnology contains the feature of improving the reaction environment, strengthening thereaction process and speeding up the reaction rate, a cavitation-impinging stream reaction device was builded, and Fenton oxidation experimental research is carried out separately inthe the ordinary reaction device and cavitation-impinging stream reaction device, theresearch based on the experiment of Fenton oxidation producing hydroxyl radicals, withmethylene blue as hydroxy free radical capture agent, and detected withspectrophotometry.The results show that: the reaction time is reduced by half in thecavitation-impinging stream reactor, and removal rate of methylene blue increased7.4percentage points.So it can be concluded that cavitation-impinging stream technology canreally speed up the reaction rate, and strengthen the reaction process.In summary, the study shows that the flow field of cavitation-impinging stream withthe formation of vortex, highly turbulent, strong pressure fluctuation and othercharacteristics, so cavitation impinging stream technology can be used to improving thereaction environment, strengthening the reaction process, and speeding up the reactionrate.The study of this topic lay the theoretical and experimental basis for the application ofcavitation-impinging stream technology.