Study On The Ozone Decomposition Characteristics Of Self-excited Pulsed Cavitation Jet

Since the beginning of the 21st century,many industries such as industry and manufacturing have been developed for a long time,but the water pollution caused by those is becoming more and more serious.At the same time,the lack of oxygen in the water caused by the expansion of the aquaculture industry has also caused people ’s enough attention.Therefore,the combination of cavitation jet and ozone decomposition is a good choice for the reason that the cavitation effect of jet cavitation can play a role in purifying the water body,and the generated oxygen also plays a role in the oxygenating of the water body,which has a very broad research prospect.The research work of this paper is summarized as follows:(1)Based on the basic principle of the formation of self-excited pulse cavitation jet,the formation,development and collapse of cavitation bubbles and the movement of a single cavitation bubble in the flow field are analyzed and calculated to determine the location of the maximum pressure of the flow field in the chamber.Turbulence model,cavitation model and multiphase flow model were determined.(2)The software platform built based on Fluent was used for the numerical analysis and simulation of the flow field in the part of the self-excited pulse chamber.The grid with a density of 220,000 and a convergence range of 1.06 has met the requirements of grid independence.Numerical analysis and simulation were carried out on the distribution of ozone and pressure in the chamber of the nozzles on the upper side and the left side,and the optimal position of ozone inlet was determined by three-line method.At the same time,it was found that the change of the position of the ozone inlet had no obvious effect on the pressure change in the chamber and did not affect the reaction of the chamber.The ozone distribution and pressure distribution under different collision angles have their respective advantages,so which collision Angle should be adopted should be compared with the subsequent cavitation reaction and chemical reaction.(3)After considering the shear stress and turbulent pulsation energy,the UDF program was introduced to modify the Schnerr-Sauer cavitation model.The simulation results showed that the formation,development and collapse of cavitation bubbles inside the self-excited pulse chamber showed periodic changes,forming empty The oscillating period of the vortex,along with the change of the cavitation vortex,the jet shows a state of convergence and divergence.The cavitation reaction inside the self-excited pulse cavitation chamber under different collision angles has little difference,but the reaction severity is different.It can be well adapted to the modified Schnerr-Sauer cavitation model.(4)Based on the photocatalytic ozone degradation and the mechanism of ozone in aqueous solution,we made some explorations and studies on the degradation mechanism of the cavitation jet after the self-excited pulse,determined many constants such as chemical reaction constant and enthalpy value,and compared and analyzed different collisions Under the angle of ozone degradation and oxygen generation reaction,it was found that different collision angles have a certain effect on the severity of the chemical reaction,affecting the amount of ozone degradation and oxygen generated.