Study On Heat Dissipation Intensification Of Composite Piezoelectric Ultrasonic Transducer

Power ultrasound has a wide range of applications in many fields such as cleaning,processing and welding.Aiming at the problems of frequency shift,efficiency drop and life shortening caused by temperature rise during the working process of high-power transducers,this paper proposes a new type of heat pipe heat dissipation ultrasonic transducer,and adopts two methods: simulation and experiment.Compared with ordinary transducers,the vibration characteristics,radiated sound field characteristics,and heat dissipation characteristics are compared.First of all,according to the similarity of the mechanics and electrical systems of the transducer,the equivalent circuit method is used to solve the complex electromechanical coupling problem of the transducer to simplify the research.The parameters in the equivalent circuit method are obtained through the admittance characteristic analysis.The resonant frequency and performance parameters of the transducer are derived based on the obtained circuit parameters,which are used as indicators for subsequent optimization and comparison of transducer performance.Further,through temperature characteristic experiment and theoretical analysis,the influence of temperature on the performance of the transducer is obtained.As the temperature rises,the performance indicators of the transducer will change,among which the drift of the resonance frequency,the increase of the static capacitance and the decrease of the mechanical quality factor are the most obvious.In order to control the heat generation from the root cause,this paper proposes the loss model of the transducer,and obtains that when the transducer is in resonance,the mechanical loss accounts for 95%,while the dielectric loss only accounts for 5%.In each component,piezoelectric ceramics The heat of the front cover is the most serious.Based on the research on the vibration characteristics of the transducer and the heat dissipation characteristics of the heat pipe,this paper proposes a heat pipe heat dissipation ultrasonic transducer.The heat pipe radiator adopts the form of a copper-water-composite wick,and uses straight fins in the condensation section to enhance heat dissipation.Six heat pipe radiators are evenly arranged along the circumference of the transducer.The specific placement position takes into account the temperature distribution and the position of the nodal surface of the transducer,and is designed on the front cover close to the piezoelectric ceramic.And the heat pipe radiator adopts thermal resistance analysis method and numerical simulation method to study,and verify its excellent isothermal and thermal conductivity.Finally,a comparative study of heat pipe type and common type transducers is carried out through numerical simulation.Compared with ordinary transducers,the average temperature of the piezoelectric ceramics in the heat pipe transducer is reduced by 60%,and the drift of the resonance frequency of the transducer is reduced by 75%.In addition,the amplitude of the output end of the heat pipe transducer is increased by 25%,and the total radiant power is increased by 38%.In order to verify the accuracy of the simulation results and the reliability of the actual operation,this paper designs heat dissipation and vibration characteristics experiments,and the difference between the experimental results and the simulation results is no more than 6%.In summary,the heat pipe type transducer can effectively solve the serious temperature rise problem of the power transducer,the operation is more stable,the radiation efficiency is higher,and further production and promotion can be carried out.