Simulation And Experimental Research On Liquid Flow Breakup By Ultrasonic Standing Wave

The ultrasonic standing wave atomization technology is a non-contact atomization technology that directly uses the energy of the standing wave sound field to break and atomize the liquid in the sound field to prepare powder.The equipment is simple,and the prepared powder has the advantages of high sphericity,less impurities,and narrow particle size distribution.Through strict control of process parameters,the particle size of the powder can be controlled,which is of great significance to the production of powder.In the ultrasonic standing wave sound field,the deformation,breaking and even atomization of the liquid droplet and liquid flow are simulated and experimentally researched.The atomization mechanism of droplets and liquid flow in the standing wave sound field and the influence law of atomization parameters is studied,and the basis for parameter selection is provided for the atomization process.Firstly,the acoustic control equation of the ultrasonic standing wave sound field was established,and the standing wave sound field model was established based on the Fluent software.Through the analysis and deduction of the acoustic radiation force equation,the sound field and the flow field were coupled,which provides a simulation basis for the liquid to be deformed and even broken in the sound field.Secondly,based on the standing wave acoustic field model combined with the gasliquid two-phase flow model,a multi-physics coupling droplet and liquid flow atomization model is established.Using User-Define-Scalars to add acoustic radiation force,the process of deformation,breaking and even atomization of liquid droplets and liquid flow in the ultrasonic standing wave field was simulated.Based on the changes in the pressure field and velocity field around the droplet and liquid flow during the deformation process,the atomization mechanism of the droplet and liquid flow deforming and breaking in the sound field was analyzed.By analyzing the breaking process of liquid flow under different parameters,the influence law of different parameters on liquid flow breaking was obtained.Finally,an ultrasonic standing wave atomization experiment device was built,and experiments were carried out on the deformation and breaking of liquid droplets and liquid flow with different parameters until atomization.The pictures of the atomization process of droplets and liquid flow were obtained through high-speed cameras,and the actual atomization process and simulation of droplets and liquid flow were compared and analyzed.The crushing and atomization experiments of palm wax and tin under the action of ultrasonic standing wave were carried out.Through the analysis of the collected powder,the influence laws of different parameters on the particle size distribution and powder morphology of the powder were obtained.