Numerical Simulation And Structural Optimization Design Of Cavitation Flow Field Of Two-stage Composite Cavitation Generator

With the transitional development and application of domestic resources,resources and the environment are under tremendous pressure.The traditional heating and heating method requires a large amount of fuel and is expensive.In the face of the current energy shortage and serious pollution of the environment caused by fuel combustion,the development of a new heating and heating method is undoubtedly a top priority.The liquid cavitation generator of the core technology does not require any heating element,and relies only on the high-speed movement of the liquid.The cavitation process of the liquid molecules generates high temperature and high pressure,and the kinetic energy is converted into heat energy,and the heat generation and the heat medium are integrated.It achieves zero emission,no pollution,good environmental protection,and the heating cost is greatly reduced.It can be widely used in heating and hot water supply in residential buildings and various buildings.The traditional hydrodynamic cavitation generator is a venturi tube and orifice cavitation device,and most of them are mainly single-stage cavitation.Compared with the single-stage cavitation generator,the two-stage composite cavitation generator will be greatly increased.The area of the zone is increased,and the cavitation collapse strength is increased,and the cavitation effect is also better.Therefore,designing a two-stage cavitation generator not only has important reference value for the optimization design of cavitation devices in engineering applications,but also has great practical significance for environmental protection and economic development.Based on the experimental research and numerical simulation of combined cavitation generator,this paper designs a new type of nested two-stage composite cavitation generator with two-stage cavitation generator as the research object.The main research contents and conclusions are as follows:(1)The cavitation system test was carried out for the integrated two-stage combined cavitation generator composed of venturi tubes and orifice plates.Through the experimental data,the optimal outlet cone angle and throat structure for cavitation effect were obtained.parameter.The experimental results show that the outlet cone angle and the throat structure of the cavitation generator have an important influence on the cavitation effect.When the outlet taper angle is between 15° and 35°,the exit cone angle of about 20° is most suitable.The progressive type of throat structure is more conducive to cavitation effects than the sharp and smooth type of throat structure.(2)The simulation calculations of different outlet taper angles and different throat structures were carried out for the integrated two-stage combined cavitation generator in the experiment.The calculation results show that within a certain range,the combined cavitation generator with the outlet cone angle of about 20° has a higher vapor content and the best cavitation effect.Compared with the sharp type and smooth type,the throat of the venturi is the same.When the structure is gradually slow,the cavitation effect is better,and the gas content in the core zone is also the highest.The simulation results are consistent with the experimental results,which proves that the simulation method is feasible.(3)According to the experimental and simulation calculation results of the integrated two-stage combined cavitation generator,the nested two-stage composite cavitation generator is designed for the structural parameters(composite position,channel length,hole arrangement)And numerical simulation analysis of operating parameters(pressure,temperature).The simulation results show that the cavitation effect is best when the orifice plate is completely nested with the venturi tube;the fully nested composite cavitation generator is best when the channel length is between 4 mm and 15 mm.The length of the hole is 10 mm;the length of the hole is 10 mm.The different arrangement of the holes in the fully nested composite cavitation generator,with a radial distribution with a central hole,cavitation relative to the annular and linear arrangement The generator has better cavitation effect;when the outlet pressure is constant,the inlet pressure has an effect on the cavitation flow field.The larger the inlet pressure is in a certain range,the higher the maximum vapor content,the better the cavitation effect;the temperature of the liquid It has an influence on the cavitation process.Due to the simultaneous action of gas content and saturated vapor pressure,the gas content dominates around 40 °C,while in other temperature ranges,saturated vapor pressure dominates.