Design And Experimental Study Of Adjustable Frequency Longitudinal Vibration Ultrasonic Oscillator

Ultrasonic vibrator is the core element of power ultrasonic vibration system,which is composed of transducer and horn.In power ultrasound applications,the ultrasonic vibrator often needs to be connected to a different load,which will cause the resonance frequency of the vibrator to change,making the ultrasonic vibrator unable to work normally and efficiently.In order to reduce the amplitude of the resonance frequency of the ultrasonic vibrator when the external load is connected to the load,the electromechanical equivalent circuit method and the Comsol Multiphysics5.3 finite element simulation software are used to design and manufacture based on the traditional longitudinal vibration ultrasonic vibrator and the electric load frequency modulation An adjustable frequency longitudinal vibration ultrasonic vibrator is introduced.This article mainly conducts research from the following three aspects.(1)Analytical method was used to design a traditional longitudinal vibrating ultrasonic vibrator with a resonance frequency of 35 kHz,and the vibrator was optimized by the finite element method.The radius of the transition arc of the stepped horn was selected.According to the influence law of the resonance frequency of the horn,it is found that for the same stepped horn,the resonance frequency of the horn increases as the radius of the transition arc increases.Then through the harmonic response analysis,the rationality of the design size and material selection of each part of the ultrasonic vibrator is verified.(2)Based on the traditional ultrasonic vibrator,through the electromechanical equivalent circuit method,combined with the finite element method,this paper designed a longitudinal vibration adjustable frequency ultrasonic vibrator,using the finite element simulation software to select the position of the FM crystal stack,and obtained The effect of the position of the FM crystal stack on the resonance frequency of the vibrator is found.When the FM crystal stack is located inside the large end of the horn,the resonance frequency of the adjustable frequency ultrasonic vibrator gradually increases as the position of the FM crystal stack gradually moves away from the end face of the input end of the horn Rise.Then according to the theoretical calculation results,the frequency equation of the vibrator is solved by MATLAB,and the relationship between the externally tuned electrical load reactance and the resonant frequency of the vibrator is drawn.From the relationship diagram,we can see that in theory,when the external load on the front and rear ends of the vibrator is not considered Within a certain range,the resonance frequency of the ultrasonic vibrator generally decreases with the increase of the reactance of the FM electrical load.(3)Two experiments were designed to investigate the effect of adding a FM inductance on the resonance frequency of the ultrasonic vibrator when there is no external load on the front and rear faces of the vibrator,and the FM inductance in the case of an external liquid load on the front end of the horn The resonance frequency of the vibrator is compared with that when the FM inductance is not added,and the frequency modulation effect of the FM inductance on the ultrasonic vibrator is investigated when the front end surface of the horn is connected with a changing liquid load.The test results show that when there is no external load on the front and rear faces of the vibrator,the resonance frequency of the ultrasonic vibrator decreases with the increase of inductance in the frequency range of 35-40 kHz;when the front end of the horn is connected with different liquid loads,the vibrator's The resonant frequency will be affected to varying degrees.After the corresponding frequency-modulated inductance is connected,the resonant frequency of the ultrasonic vibrator will be compensated to a certain extent,and it can return to the original set resonant frequency value.The test verifies the correctness of the frequency modulation theory of electric load and the effectiveness of adjusting the frequency modulation inductance connected to the frequency modulation crystal stack to solve the problem of frequency drift of ultrasonic vibrators under different loads.Research shows that the adjustable frequency longitudinal vibration ultrasonic vibrator designed in this paper has good frequency adjustment performance and can be used in power ultrasonic machining and cavitation tests.