| China is a country with a shortage of available water resources.In the total water consumption of the country,the water consumption of irrigation districts accounts for a high proportion.Improving the water efficiency of irrigation districts is of great significance to saving water resources.Accurate measurement of water consumption of irrigation districts is the key to improving water efficiency of irrigation districts.This paper combines theoretical analysis,actual experiment and numerical simulation to study the impact of different sediment content on the accuracy of the pendulum flow measurement device under different flow conditions with different sediment content,and draws the following conclusions:1?The theoretical analysis of the structure and principle of the pendulum-type flow measurement device is carried out,and the general flow measurement formula for the flow measurement of the flow measurement device is obtained,and the selected pendulum rod is made of stainless steel and the diameter is 5 mm.Experiments,through actual tests under different working conditions,obtained the following conclusions;(1)A flow measurement test was carried out on a U-shaped channel under clear water.It was found that the measured instantaneous flow of the channel matched the result of theoretical analysis by using the flow measurement device.The channel condition was measured through the test under clear water.The coefficient K of the general flow measurement formula below.(2)The flow measurement experiment was carried out in U-shaped channel flows with different sand content.By changing the size of the sand content in the channel flow,the impact of the different sand content on the accuracy of the pendulum flow measurement device was studied.Through experiments,it is found that when the instantaneous flow rate of the channel remains unchanged,with the increase of the sand content,the swing angle of the pendulum rod of the flow measuring device also becomes larger.In the range of 0-50 kg/m~3 of the sand content,the pendulum The swing angle of the rod has a certain relationship with the sand content in the channel water flow.2?The computational fluid dynamics software Fluent was used to numerically simulate the impact of different sand content on the pendulum rod.(1)The materials involved in the entire simulation are air,water,and sand.This simulation needs to fully consider the mixing between water and sand,as well as the boundary between water and sand mixture and air.Therefore,the water and sand model in this simulation mainly adopts the Eulerian model and the 6DOF dynamic grid model;(2)Through the numerical simulation study on the influence of sand in the water flow with different sediment content on the accuracy of the pendulum rod flow measuring device,it is found that in the U-shaped channel,the corresponding pendulum rod swing angle under the water flow condition of 0-50kg/m3 is found.,The water surface line of the channel,the flow velocity distribution of the channel crossing section,and the flow velocity change of the crossing section are consistent with the actual situation.Comparing the experimental flow measurement data with the numerical simulation results,it is found that it is feasible to use Fluent to conduct numerical simulation to study the flow measurement characteristics of the flow measurement device.In this paper,through the method of combining actual test and numerical simulation,the influence of the change of the sediment content of the water flow on the accuracy of the pendulum-type flow measurement device under the conditions of different sediment content flow is studied,and the flow measurement pendulum rod under the action of water flow is obtained.For the swing angle,the actual test and numerical simulation results are compared and analyzed,and the flow measurement formula of the flow measurement device including the influence factor of the sand content is obtained,which is helpful for the application and promotion of the pendulum-type flow measurement device. |
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