چكيده به لاتين
The use of ultrasonic flow meters is expanding, and the majority believe that this kind of technology has high precision in every application and every local, and is superior to other types of current meters. In the present study, the piezoelectric sensor's performance in the liquid ultrasonic flow meter is numerically investigated. For implement of ultrasonic measurement of any type, acoustic transducers are usually the most important parts of the system, which can significantly affect the accuracy or functionality of a system. The current numerical work has begun through the need to increase the understanding of the theory and modeling tools in relation to the simulation of the transducer, in particular ultrasonic transducers for use in transit time ultrasonic liquid flowmeters. To investigate the effect of different parameters on piezoelectric sensor's performance in ultrasonic flowmeters, the research was carried out numerically. In numerical research, the piezoelectric transducers performance modeling in the ultrasonic flowmeter was divided into three sub-models. Parts that model piezoelectric transducers use conventional FEMs, while ultrasonic wave propagation is modeled by the DG method. The results of a numerical study to investigate the effect of fluids temperature (water, light, heavy, and medium crude oil samples) on the performance of optimal piezoelectric sensor in accordance with the results reported by other researchers. Among the 6 types of piezoelectric material used in this research, piezoelectric with PZT-5H material was selected as optimal piezoelectric. The reason for choosing this piezoelectric is that the maximum voltage is greater than other piezoelectrics in 4 types Various fluids (water, light, heavy, and medium crude oil samples). The flow rate of the simulated flow inside the flowmeter is acceptable by the standard k-ε model, since the error created (5.69%) is low compared to the original value. By applying 6 types of different materials as an impedance matching layer, the result was that an epoxy matching layer for piezoelectric sensors in water and heavy crude oil is appropriate because 50% of the power Increases the signals within the fluids. Also, the use of polyester as an impedance matching layer for an optimal piezoelectric transducer in light and medium crude oil samples increases the efficiency of the signal generated by the converter by 60%.
Keywords: Piezoelectric, matching layer, speed of sound, Ultrasonic flowmeter, Transit time.
