The Cavitation And Spray Characteristics Research Of Atomizing Nozzle Based On Self-oscillating Pulse Effect

It’s one of the hotspots in the field of atomization development that use of the self-excited oscillation pulse characteristics to improve fluid spray atomizing effect.The self-excited oscillation pulse jet does not require external excitation source,it is able to generate a pulse jet by the structural characteristics of the self-oscillation chamber itself.As it has a larger swing characteristics and cavitation characteristics,rational design of a self-oscillating spray nozzle structure can effectively improve the atomization quality and saving spray energy.Based on the deeply research for the cavitation characteristics of the self-excited oscillation pulse jet,this article analysis the influence of cavitation effect on jet atomization and proposed a design method based on atomizing nozzle self-oscillating pulse effect.The main work made herein are as follows:(1)Based on the atomization theory caused by cavitation bubble breaking and the cavitation forming process of self-excited oscillation pulsed nozzle’s outlet channel,the jet cavitation effect on the self-excited oscillation pulsed jet atomization effect is analyzed.Put forward the method that using the self-excited oscillation pulsed effect of cavitation jet to promote jet atomization.(2)On the basis of self-excited oscillation pulsed atomization nozzle structure,the influence of the jet velocity and fluctuating intensity for the cavitation effect of nozzle’s outlet channel are analyzed,meanwhile,the flow Reynolds number and fluctuating pressure are raised for demonstrating the outlet channel cavitation degree,and the Reynolds number and the nozzle chamber aspect ratio are acquired which could guarantee better cavitation state of nozzle’s outlet channel based on the self-excited oscillation pulsed nozzle finite element analysis.(3)Based on the forming principle of cavitation air bag produced by self-excited oscillation pulsed effect,the simplified physical model of cavitation air bag at the energy of aggregation and release state is established in the self-excited oscillation cavity and the influence of energy aggregation effect on self-excited oscillation jet atomization is studied.(4)The structural design method of atomizing nozzle chamber wall surface is putforward based on cavitation air bag energy maxmization.The corners of the wall transition shape is reconstructed by using the Bezier curve,a new type of spray nozzle of self-excited oscillation chamber wall structure is designed and the cavitation air bag distribution and the jet exit velocity in the chamber are calculated and analyzed.(5)Spray characteristics study on new self-oscillating spray nozzle which been proposed by the structure design method previously described by using the VOF multiphase flow model of Fluent software.Focuses on the ability to characterize the properties of the spray volume fraction of multiphase flow field,the distribution of turbulent kinetic energy and speed characteristic parameters.