Irrigation area channel flow measurement method based on gradient effect of semi-cylindrical rectangular grooves on two sides

Abstract

The invention discloses an irrigation district channel flow measurement method based on the gradient effect of semi-cylindrical rectangular grooves on two sides, which comprises the following steps of: verifying a numerical simulation method, performing numerical calculation and physical test on rectangular grooves with different gradient, and performing data analysis and comparison to obtain an accurate CFD (Computational Fluid Dynamics) setting method. And numerical simulation is carried out on the semi-cylindrical rectangular grooves with different ratios on the two sides through the obtained CFD setting method, after calculation is completed, the water depth and the shrinkage overflowing width under the conditions of different ratios, shrinkage degrees and flow are output, and data processing is carried out through SPSS and Origin to obtain a new flow prediction formula. During CFD numerical calculation, cloud calculation is introduced to improve the calculation precision and efficiency of CFD. The semi-cylindrical rectangular grooves on the two sides are arranged in a channel under any gradient condition, and after water flow is stable, the measured water depth and the corresponding gradient value are substituted into a flow formula considering the gradient effect, so that the real-time channel flow can be obtained. The channel flow can be accurately tested, operation is convenient, manufacturing is low in cost, and adaptability is high.

Description

technical field [0001] The invention relates to a channel flow measurement method in an irrigation area based on the slope effect of a semi-cylindrical rectangular trough on both sides, and belongs to the field of water conservancy engineering. Background technique [0002] Water management in irrigation areas is crucial to the construction of irrigation areas. Water management in irrigation areas mainly refers to the reasonable adjustment and distribution of irrigation water volume, flow and irrigation time, so as to maximize the benefits of irrigation and drainage projects, effectively use irrigation water sources, improve irrigation water quality and efficiency, and promote agriculture. Stable and high yield. In recent years, the state has vigorously led the intelligent and intelligent development of irrigation areas. The inherent meaning is to reform the traditional operation methods of irrigation areas through advanced technology. Therefore, it is particularly important...

AI Technical Summary

Problems solved by technology

(1) Measuring water by using canal buildings refers to measuring water by using gates, aqueducts, inverted siphons or falling buildings. This kind of method has high measurement requirements, and the buildings themselves must not be damaged, deformed, leaking, silted, blocked, etc. phenomenon, and the calibration and maintenance of internal test equipment are relatively difficult, and the test methods are cumbersome, which is not conducive to application

In addition, using canal buildings to measure water, the first task in engineering application is to build corresponding buildings, which requires a lot of manpower, material and financial resources

(2) There are four main ways to measure water by using ad hoc water measurement settings: First, use a U-shaped channel, a flat-bottomed parabola, and a rectangular groove without a throat section to measure the water. This method has certain defects, and the accuracy of its predicted flow rate Poor, because the scale effect is not considered in the coefficient calibration, the discharge coefficient checked on the model scale is bound to be inaccurate when applied to the prototype scale, the velocity coefficient has a lot of experience, and the scope of application is small, only It is used for flat-bottomed channels and cannot be moved once it is built; secondly, Parshall measuring rectangular trough is also a water measuring facility composed of open channel contraction, which has harsh flow measurement conditions, high design and installation requirements, and large measurement errors; Third, the triangular water measuring weir has a simple structure, low cost, convenient testing, and relatively high accuracy, but the water passing capacity is small, the calculation is complicated, and the versatility is poor; Fourth, the trapezoidal water measuring weir has a simple structure and low cost. Inexpensive and easy to test, but when the water level in front of the weir is high, siltation and congestion will occur in channels with poor water quality, it can only be used for flow measurement in clean water, and the technical requirements for users are relatively high in installation and use. Poor; using the flow meter to measure the flow, the flow measurement process is cumbersome, takes a long time, and the measurement accuracy is poor, so it is difficult to popularize and use it in irrigation areas

However, in the prior art, there is no method for predicting the flow rate of semi-cylindrical rectangular grooves on both sides by means of numerical experiments.

Chinese patent CN201910015788.6 discloses a method for predicting the critical submergence depth of a wet chamber pump station through CFD. In this patent, CFD is used to predict the critical submergence depth of the pump station, but the method cannot be used to predict the flow rate of the central cylindrical rectangular tank. CN201811325431.X discloses a method for predicting the flow rate of large-scale low-lift water pumps. In this patent, the flow rate of large-scale low-lift water pumps is predicted by using CFD combined with the differential pressure flow measurement method. Similarly, the method cannot be used for the channel flow test of this application

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