Propagation Characteristics Of Ultrasonic Wave And Numerical Simulation Of Droplet Agglomeration In Wet Steam

The presence of wet steam in the final stage of the steam turbine and the nuclear power plant units has a great impact on the safe and efficient operation of the power plant.The monitoring of the thermal parameters of wet steam,the monitoring of saturated water droplets,and the removal of wet steam droplets have been urgent problems to be solved.In order to investigate the application of ultrasonic technology in the field of wet steam monitoring,this paper uses numerical simulation methods to study the ultrasonic propagation characteristics in wet steam media and the characteristics of wet steam droplet trapping under high-intensity ultrasonic fields.Through the analysis of the calculation results,the feasibility analysis of the application of acoustics in the measurement and prevention of wet steam is provided,which provides a numerical reference and theoretical basis for future experimental research and engineering practice.The first part of this paper is based on the ECAH mathematical model of ultrasonic propagation in a granular two-phase flow medium.The calculation model is reasonably modified for the characteristics of wet steam saturated droplets,and the effects of changes in ultrasonic frequency,droplet radius,wet steam temperature,and humidity on The influence of ultrasonic sound velocity and ultrasonic attenuation coefficient was used to investigate the influence of droplet size distribution on the ultrasonic propagation characteristics,and the measured parameters of the final wet steam of the steam turbine were used to calculate the acoustic propagation characteristics.The conclusion is that different factors have different degrees of influence on the ultrasonic propagation characteristics in wet steam.The impact of the droplet size on the ultrasonic propagation characteristics is dominant;the droplet size distribution has an influence on the ultrasonic propagation characteristics.Low-frequency ultrasound The measurement of sound attenuation coefficient is stable and the resolution is large.Ultrasonic changes have good theoretical support for inversion of droplet size and humidity in wet steam.The second part of this paper is aimed at the phenomenon of agglomeration effect of wet steam droplets in a strong sound field.Based on the multiphysics coupling simulation software COMSOL,the simulation and study of ultrasonic standing wave field capture and agglomeration of wet steam droplets are carried out.It mainly includes analyzing the agglomeration mechanism(relaxation time analysis,droplet collision analysis),setting reasonable sound field,flow field,and droplet parameters,modifying the forces between droplets in the simulation model,and realizing standing wave field,flow field,and droplet motion.Based on the calculation results,the effects of different factors on the capture and reunion effects are analyzed based on the calculation results.The conclusion is that the sound standing wave field has a good capture and agglomeration effect on wet steam droplets.The droplet capture effect and agglomeration efficiency are related to the ultrasonic frequency,the particle size of the wet steam droplets,and the sound pressure level;it is feasible through engineering applications.According to the nature analysis,it is considered that it has high engineering value in some scenarios in the power station,but there are technical problems that need to be solved.Finally,the mathematical model used in the calculation of this paper is analyzed,and related improvements and suggestions for future research directions of ultrasonic technology and wet steam research are put forward.