Research On Acoustic Field Characteristics In The Mental Pipe Under Ultrasonic Vbration

With the shortage of global energy,nuclear energy has been widely used in production in recent years as a clean resource,replacing the status of traditional energy gradually.When using nuclear energy to generate electricity,it is necessary to transport nuclear materials through the metal pipes.During the long-term use of metal pipes,the fouling will inevitably deposit on the inner wall of pipes.The existence of these fouling seriously affects the efficiency of pipe transportation.When it accumulates to a certain extent,it may be blocked which will cause incalculable consequences.Therefore,it is an urgent problem to clean the fouling on the inner wall of metal pipes under the condition of ensuring safety and equipment efficiency.When the ultrasonic vibration is applied to the outer wall of the metal pipe,the cavitation generated in the liquid inside the metal pipe will create an extreme physical environment of high temperature and pressure locally and high-speed microjets which will clean the fouling attached to the inner wall of the pipe.Based on the mechanism of ultrasonic cleaning for metal pipes,the characteristics of acoustic field in the metal pipe under ultrasonic vibration were studied by simulation and experiment in this paper.The specific research work includes:Firstly,the mechanism of ultrasonic cleaning for metal pipes was studied and analyzed in this paper.Based on the theory of ultrasonic cavitation,the conditions and forms of cavitation in the metal pipe under ultrasonic vibration were derived,and the motion state of cavitation bubbles was analyzed.According to the theory of acoustic wave propagation,the acoustic wave equation of ultrasonic wave propagating in the liquid inside the metal pipe was obtained.In addition,the various attenuation conditions in the propagation process were analyzed.The reflection and refraction coefficients were calculated using the theory of acoustic radiation when the ultrasonic wave reflects and refracts in the metal pipe.Secondly,the simulation of acoustic field in the metal pipe under ultrasonic vibration was carried out.The multi-physics simulation software COMSOL was used to simulate the distribution of the acoustic field,and the variation of acoustic field and the area where cavitation occurs in the metal pipe was analyzed.The influence of ultrasonic parameters and pipe parameters on acoustic field was studied."percentage of cavitation" was used to evaluate the effect of ultrasonic cleaning,and the optimized parameters of ultrasonic cleaning for metal pipes was obtained.Finally,the experimental study on the acoustic field in the metal pipe under ultrasonic vibration was carried out.The experimental device for ultrasonic vibration of the metal pipe was developed.By combining the hydrophone with the spectrum analysis,the cavitation energy of acoustic field was obtained by energy separation method.The distribution,size and variation of acoustic cavitation field in typical locations inside the metal pipe were analyzed which were compared and verified with the results of simulation.