Numerical Calculation of Ultrasonic Signal Propagation Characteristics in Steam System of Nuclear Power Plant

The droplets entrained by the wet steam working medium of nuclear power plant pose a threat to the economy and safety of nuclear power plant. The humidity of steam is directly related to the working efficiency of nuclear power plant. In this paper, the ultrasonic attenuation coefficient in single-phase saturated steam is calculated. Based on the simplified ECAH model in the long wave region, the ultrasonic attenuation coefficient at different frequencies and the relationship between droplet size and humidity in the steam system of nuclear power plant are numerically simulated. For the relationship between droplet size, ultrasonic frequency, steam humidity and ultrasonic energy attenuation coefficient, the results are calculated and analyzed. Results and conclusion: through numerical simulation, the influence of hysteresis attenuation coefficient on the total ultrasonic attenuation coefficient in single-phase saturated steam medium can reach 90%. In single-phase steam medium, the fluctuation of temperature and pressure has little influence on the ultrasonic attenuation coefficient, while the deviation of ultrasonic frequency will have a large error on the ultrasonic attenuation coefficient in steam. The ultrasonic attenuation method is feasible for on-line measurement of steam humidity in nuclear power plant. Compared with the steam environment under other working conditions of nuclear power plant, the ultrasonic attenuation method is more suitable for the measurement of wet steam humidity under the conditions of humidity less than 9% and droplet size greater than 4μm.