Measurement Method Of Ultrasound Attenuation For Oil Phase Fraction In Oil-water Two-Phase Flow

Oil-water two-phase flow is widely existed in industrial production and transportation process.To achieve accurate measurement of the flow parameters is the inevitable trend of industrial modernization.However,due to the complex changes in the flow process,measurement of the main flow parameters is very difficult.Ultrasonic method has become the research focus of many domestic and foreign scholars,because it's cheap,no interference to the flow process and suitable for harsh industrial environment measurement.The ultrasonic attenuation method is used to measure the oil phase fraction and particle size in oil-water two-phase flow.The finite element analysis method was used to simulate the fluid with different range of oil phase fraction and different flow patterns,and the propagation process of ultrasound was analyzed.The oil-water two-phase flow experiments verified the simulation results.The specific research work is:(1)According to the principle of ultrasonic attenuation test method,finite element analysis method was used to study the effect of three influence factors,which are ultrasonic operating frequency,size of discrete particle,position of discrete particle,on ultrasonic attenuation model.(2)For the measurement of oil phase fraction in the oil-water two-phase flow during low oil phase fraction range and phase inversion section,the finite element simulation models are established respectively for three flow patterns,which are O/W pattern,D W/O & D O/W pattern and ST&MI pattern.The sound pressure distribution of ultrasonic propagation is obtained.The relationship between ultrasonic attenuation coefficient and oil phase fraction is analyzed.The specific attenuation characteristics of ultrasonic in oil-water two-phase flow are investigated respectively in three flow patterns.(3)For the measurement of discrete particle size in the O/W pattern flow during low oil phase fraction range,a BLBL(Bouguer-Lambert-Beer-Law)model is selected to characterize the relationship between ultrasonic attenuation and droplet size distribution.The finite element analysis method is used to design a fixed particle size distribution simulation model,and the measurement particle size distribution is obtained by solving the inverse problem of the attenuation model.The feasibility of the ultrasonic attenuation method for the measurement of the droplet size is proved by comparing the measurement results and the set value.At the same time,it is verified that the BLBL model can characterize the ultrasonic attenuation mechanism of oil-water two-phase flow with O/W pattern and low oil phase fraction.(4)The ultrasonic measurement experiment of oil-water two-phase flow was carried out by using the oil-gas-water multiphase flow experimental device.And the experimental data is obtained.By comparing the experiment results and simulation results with different flow patterns,the rationality of the simulation models is verified.