Research On A New Type Of Coupling Cavitation Impining Stream Generator

The Coupling cavitated impact flow generator is a kind of occurrence device of the self-pulse emission and a key component of the cavitated impact flow reactor.The coupling cavitated impact flow generator modulates fluid flowing into the reactor.The jets will have higher kinetic energy and more cavitation bubbles.Such jet collisions in the reactor can provide an excellent chemical reaction environment.The original design is for chemical wastewater treatment and degradation of organic matter.However,there are insufficient design methods,the theory of the natural frequency of the generator and the effective feedback relationship can't guide the design very well,and the parameter ratio in the generator still uses empirical values.This paper first analyzes the mechanism by which the harmonic cavity of the organ tube produces the air-piped airflow of self-exciting pulses and The relationship between the initial pressure fluctuation frequency of the organ tube and the vortex shedding frequency is established.I designed the vortex shedding frequency experiment and deduced the relationship between the Strouhal number and the Reynolds number,known as the St-Re relationship.The expression of the natural frequency of the resonant cavity of the organ tube is obtained by the correlation between the singular frequency of the natural frequency of the resonant cavity of the wind organ and the multiple of the frequency of the initial pressure fluctuation.The arrangement sequence of the Helmholtz resonant cavity and the organ tube resonant cavity in the cavity impact flow generator is obtained by fluid network theory.The scale design of some key dimensions is carried out using the experience formulas of St-Re relational and "organ tube resonant cavity" and "Helmholtz resonant cavity".Then,the transmission matrix is solved by the fluid network theory,and the relationship equation between the natural frequency and geometry of the coupling cavitated impact flow generator is obtained.The key dimensions are brought into the relational equation and the coupling cavitated impact flow generator is designed with the existing design experience.Fluent software is used to numerically simulate the internal flow field of the air-chemical impact flow generator.By analyzing the formation process of cavity,the apparent shrinkage and expansion of air-filled airbags in the resonant cavity is observed,which proves the rationality of the design.The inlet pressure from 0.3 to 1.5Mpa and the length of the 15 to 45 mm outlet hole were analyzed.The generator export pressure,the export kinetic energy increases with the increase of the pressure,and decreases with the increase of the export hole length.Compared with the indented generator,the peak of export pressure can be increased by20% at 0.5Mpa inlet pressure,and the optimal target range can be increased by about 50 mm,which proves the rationality of the generator design method.The experiment subsequently tested the optimal target range and strike force of different outlet hole length and different inlet pressure,and obtained the influence of the inlet pressure and the export hole length on the optimal target range and the size of the peak of the strike force,and the experimental data laid the foundation for the design of the subsequent impact flow equipment.