Applied Research And Design Of Airfoil-Shaped Measuring Flume

Airfoil-shaped measuring flume is a kind of equipment which can prompt a critical water-flow to measure of the flow of water. It can be directly built in the original or new prism channels, without changing section structure of channels, and it is particularly well adapted for use in symmetrical rectangular, U-shaped cross section. Airfoil-shaped measuring flume and the channel have the same symmetry axis.This article introduced the principles and structure of airfoil-shaped measuring flume, and obtained dimension harmonious flow calculating formula through the dimensional analysis. Applied research has been carried on the ailfoil-shaped measuring flumes which have been constructed Separately in the rectangle channel of Yinda project total main channel in the Gansu Province and U channel of Shahao canal in Inner Mongolian He Tao irrigation area.During the measuring flume running process, ultrasonic current meter, electromagnetism current meter, oar current meter, ultrasonic flowmeter, pressure transmitter, ultrasonic sensor, plumb, level gauge, and so on, was used to collect Real-time data, in order to research on the water measuring performance and the actual running effect.At the same time, airfoil-shaped flume was constructed in the hydraulic experiment hall in Northwest A&F University based on the Yinda project total main channel's water measuring flume according to 1:7.5 ratio to carriy on the model experiment, which is the complementarity to the applied research.According to the applied research measured data and the model experiment data, we foune that the water measuring precision of airfoil-shaped measuring flume meets the requirement of water measuring standard, and satisfies the practical application condition.Through further analyzes, we obtained some performance parameters in the airfoil-shaped measuring flume application, such as submerged extent, Fr of upstream, form of hydraulic jump downstream, head loss, backwater hight, and so on.Summarizing the mating reaction of the airfoil-shaped measuring flume and the water level automatic monitoring system in the application, the thesis considers that with characteristics of good continuity during real-time monitoring and high sensitivity, airfoil-shaped measuring flume is a new water measuring flume which is surtable for modern management in irrigated areas. Through analyzing the test data in the critical circumstances, we found that there is a linear relation between contraction ratio of the airfoil-shaped measuring flume and the channel bottom slope under the constant flow circumstance, and the contraction ratio creases along with the slope increases.The contraction ratio and slope relation table of airfoil-shaped measuring flume was obtained, according to the linear relation computation. The paper induces preliminary design method step of airfoil-shaped measuring flume in the rectangular channel, and has displayed rectangular ditch section condition and the fluent condition in application to airfoil-shaped measuring flume, as well as the requirements of airfoil-shaped measuring flume installment and water level survey.