Research On The Vibration Mechanism And Testing Method Of Electro-hydraulic Dual Excited Electrospray Needle

Vibrations on the electrospraying needles which are excited by electro and hydraulic fields,often go hand in hand in the process of electrospraying,the spraying stability and atomizing results may be affected by it greatly.Detecting the vibration law of the electrospray needle during the electrospray process,and analyzing the mechanism of vibration,can find some ways to reduce the vibration.Based on this,a new method for testing the electrohydraulic excitation characteristics of the electrospray needle—optical energy method is proposed.It uses high-frequency infrared light of a specific wavelength as the signal carrier,and determines the frequency of the electrospray needle vibration by detecting the change in light energy caused by vibration on the effective receiving plane of the photoelectric receiving device.In the detection process,the concepts of "modulation" and "demodulation" in radio transmission are used to process the signal,which effectively reduces the influence of environmental stray light on the test results.On the basis of fully demonstrating the rationality of the detection principle,The measuring circuit and test platform are designed and established.Vibration test of the spray process of the electrospray needle is carried out under different test conditions,and the conditions for the electro-hydraulic excitation phenomenon of the electrospray needle are obtained through analyzing the test results.Then,the vibration mode of electrospray needle is analyzed by ANSYS Workbench,and the natural frequencies and modal shapes of different specifications of electrospray needle are obtained.The relationship between the Electro-hydraulic Vibration Phenomenon of electrospray needle and its natural frequencies is obtained by comparing with the experimental results.At the same time,the atomization particle size test was carried out,and the influence of Electrohydraulic Vibration on atomization particle size was analyzed.Finally,based on the above theory and experimental results,the vibration mechanism of the needle is analyzed,and three methods to weaken the Electro-hydraulic Vibration of the needle are found out.The experimental results show that: the vibration frequency of the needle increases with the increase of the applied voltage and the liquid flow rate;the relationship between the vibration amplitude and the liquid flow rate is small,and increases with the increase of the applied voltage;the larger the length diameter ratio of the needle,the more likely the Electrohydraulic Vibration phenomenon occurs,which is in line with the results of modal analysis.The Electro-hydraulic Vibration of the electrospray needle makes the distribution of droplet size larger and the monodispersity is lost.In the process of electrospray,the force produced by droplet breaking,the force of charged fluid in the electric field and the vibration of liquid flow inside the needle are the main reasons for Electro-hydraulic Vibration of the needle.There are three ways to weaken the Electro-hydraulic Vibration of the electrospray needle:1.atomizing under the condition of reasonable voltage and flow rate;2.adopting appropriate electrode configuration;3.improving the mechanical structure of the needle.The most effective way is to improve the mechanical structure of the needle.