The Evolution And Collapse Characteristics Of Bubble And Bubble Cluster In Venturi

Because of the simple reaction equipment,the high efficiency of the using of the energy, no secondary pollution and achieving scale easily,the hydrodynamic cavitation has broad foreground of application.In the course of the cavitation,some extreme conditions such as high temperature,high pressure and free radicals generated by the violent collapse of cavities can achieve and intensify the special physical and chemical processes.However,the research of hydrodynamic cavitation is studied mainly by experiment and lack of theory.In order to achieve the optimal enhancement effect of the hydrodynamic cavitation,the further research should be expanded.In order to explore the mechanism of cavitational enhancement,find out the basic disciplinarian of influencing the effect of cavitational enhancement,realize the infection of the evolution and the enhancement effect of cavitation by every factor,build the relationship between enhancement effect and influencing factors and direct the optimization design of hydrodynamic cavitational reactor,the article has expanded the following missions.The numerical study of single gas-vapor bubble:Based on Gilmore equation that considers the viscosity and the condensability of liquid,combining the calculation of gas pressure under different energetics model,the article has built three mathematics models, calculated the evolution of bubble,collapse pressure and collapse pressure and then compared with experimental data,finally established the energetics model of van der Waals equation combined with polytropic assumption has the highest precision.The model has been applied to calculate the evolution of bubble,collapse pressure and collapse temperature.At last,the distributing range of the initial radius of bubble has been attained when cavitation happens, the influence of the evolution of bubble,collapse pressure and collapse temperature by every factor has been discussed,the subentry and integer correlation of the parameters and collapse pressure and collapse temperature has been built.The study of collapse characteristic of gas-vapor bubble cluster:On the basis of energy transfer theory,the model of collapse layer by layer and reciprocity of bubble in the cluster, the article has built three models for calculating the collapse pressure of bubble cluster.From the comparatively results,we know that the reciprocity of bubble in the cluster accelerates the collapse of bubble cluster and augments the collapse pressure of bubble cluster,the infection of the collapse bubble between each layer is more remarkable than that in the layer.Applying the model of collapse layer by layer that considers the infection of bubble collapsed between each layer and bubble collapsing in the same layer,the article has calculated the collapse pressure of bubble cluster with different parameters,discussed the relationship of the collapse pressure and infection parameters,established the subentry and integer correlation of the collapse pressure of the bubble cluster and the parameters.The numerical calculation of the cavitation region:On the basis of the assumption of no reciprocity between the bubbles of the cluster in the growth period,the growth model of bubble cluster has been built,and then the growth contour line of bubble cluster has been calculated. Afterwards,the model has been modified to calculate the collapse contour line,then the outline of the cavitation region has been obtained combined the growth contour line and compared with experimental data to validate the model is correct.On the basis front,the article has calculated the volume of the cavitation region and analyzed the relationship of the volume of the cavitation region and infection parameters.