Research On Ultrasonic Open Channel Flowmeter

Recently, water resource is becoming more and more rare, the price for water supply is higher and higher, which require that the measure precision of water flow should be rather high, especially for large piloting or city water supply. Because very small measure error may bring much great flow error, thus bringing considerable economic loss. In this paper, a high precision ultrasonic flowmeter has been researched, which is applied to large flow and convenient usage. The main contributions are as follows.Firstly, the history, present status and trend of flowmeters were introduced. The theory and characters of ultrasonic flowmeters were given, the reason for ultrasonic flowmeter was given. The main tasks of this project were brought out.Secondly, a brand new measurement method—the multi-beams method was deeply discussed. The principles of emitting and receiving were introduced; also the principles and characteristics of this method in determining ultrasonic receiving point and getting time difference were introduced. Based on the theories of probabilities and statistics; Least-Mean-Square error method is brought to estimate time difference in the multi-beams method. In addition, ultrasonic transducer was introduced in its research and development.Thirdly, hardware circuit was discussed and designed in detail, some technical matters were deeply considered, such as chip selection and parameters calculation.In the end, experiment data was researched and processed, and measurement results were achieved well. In addition, the tasks in the paper were summarized, and next research direction was pointed out.