Simulation Of The Influence Of Swing Rod Parameters On The Accuracy Of Swing Rod Open Channel Flow Measuring Device

China is a country with serious water shortage.Agricultural water use accounts for a considerable proportion of the total water consumption of the country.Improving the utilization rate of agricultural water is of great significance to the protection of water resources.Precision water measurement in irrigation areas is the key to improving the utilization rate of agricultural water.In order to improve the accuracy of water measurement in irrigation areas,through theoretical analysis,experimental study and numerical simulation,the flow measurement characteristics of swing-rod open channel flow measurement device were studied.The following conclusions were obtained:1.Based on the theoretical analysis of the principle of flow measurement with swing-rod open channel flow measurement device,indoor and field tests were carried out on D50 U-shaped channel with slope of 1/1000 using swing rods with three different materials?plexiglass,aluminium and stainless steel?and three different diameters?3mm,4mm and 5mm?.Found that:?.The main principle of the measuring device based on STM32microcontroller circuit is to measure the flow through the relationship between the swing angle of cylindrical swing rod and the instantaneous flow rate of the channel cross section.The device has high accuracy,easy to carry,simple operation,low price,and can realize synchronous reading online and offline.It provides a reliable new water measuring method for irrigation area;?.Through theoretical analysis and laboratory and field experiments,the flow measurement performance of the swing-rod open channel flow measurement device in the standard D50 U-shaped channel with slope of1/1000 was studied.It was found that when the swing-rod open channel flow measurement device was used to measure the flow in the channel,the relationship between the instantaneous flow Q of the channel cross-section and the swing angle sin^2.5?is proportional function.The general expression of the flow measurement formula is Q=K sin^2.5?;?.Three different materials and three different diameter swing rods were used to measure the flow in D50 U-shaped channel with slope of 1/1000.The relative error between the measured flow and the actual flow was small.The coefficient K in the flow measurement formula increases with the increase of the density and diameter of the swing rod.Through the analysis of the flow measurement error and sensitivity of the swing rod with different parameters,the selection criteria of swing rod parameters for swing-rod open channel flow measuring device were obtained in D50 U-shaped channel with slope of1/1000.2.Through the understanding of the research status of numerical simulation,it was found that the Realizable k-?turbulence model,VOF method for gas-water two-phase flow and 6DOF dynamic mesh model provided by CFD software FLUENT can accurately simulate the flow measurement characteristics of the swing-rod open channel flow measuring device.3.Three different materials and three different diameter swing-rods were used to simulate the flow measurement characteristics of the swing-rod open channel flow measuring device.By comparing with the actual test data,it was found that the water surface line,velocity distribution of the cross section and the swing angle of the swing rod obtained from the numerical simulation of the flow measuring characteristics of the swing-rod open channel flow measuring device were consistent with the actual situation,so,it was completely feasible to use FLUNET software to simulate the swing-rod open channel flow measuring device.Based on the study of the flow measurement accuracy of the swing-rod open channel flow measuring device with different swing rod parameters,this paper put forward the selection standard of the swing-rod open channel flow measuring device under the D50 U-shaped channel with slope of 1/1000,and explored the feasibility of the numerical simulation method,improves the flow measurement accuracy of the swing-rod open channel flow measuring device,and provided a more pracital method for precise water measurement in irrigation area.