Numerical Simulation For Three Gorges Site And Experimental Model

With the development of the national economy, accurate measurement is becoming a requirement for large flow water. The ultrasonic flowmeter has been used widely at large flow water metering, and has completed the national vet regulation abort ultrasonic flowmeter. Because of the lack of adequate experimental data to support, this regulation only lists the real flow calibration method , however , so big like the three gorges project it can not be generally real flow calibrated, and the measurement uncertainty of ultrasonic flowmeter also must be controlled at the specified range. The manufacturer of ultrasonic flowmeter has their own calculation model and claims of uncertainty, but the technical institutions have no means that verify the measurement uncertainty.In order to solve the problems of evaluation of ultrasonic flow measurement accuracy, based on CFD software FLUENT, for the three gorges project site conditions, multiple sets of measurement of fluid boundary conditions to simulate multi-channel ultrasonic flowmeter of the working process were designed. The applicability, correctness and accuracy evaluation of ultrasonic flowmeter were acquired.Through the simulation, the velocity profile of ultrasonic flowmeter installation position under different conditions was obtained, and the flow pattern of the place of ultrasonic flowmeter installation impact tremendous on measurement accuracy after data processing and analysis were obtained. By comparing the experimental model of the three gorges project, adopting a 45-degree installation angle and Gass-Jacobi calculation model are effective enough to improve the measurement accuracy of ultrasonic flowmeter.