| Water resources account for only 6% of the world in our country,and the lack of water resources has become one of the main factors that restrict the development of my country’s economy.Water shortage and how to develop agriculture water saving is the main problem that my country must face,solving the shortage of water resources,and the development of agricultural water-saving technology is related to my country’s food security and is also related to ecological security.The current water waste is still generally,and imperfect irrigation techniques and unreasonable irrigation methods have exacerbated water shortages.In recent years,my country has made a certain progress on the road to promote water-saving technology in agriculture,but there is still a long way to go.The promotion of agricultural irrigation water saving technologies still has a large difficulty,and is subject to a variety of factors.It is mainly manifested in the development of agricultural irrigation water-saving technologies,the water management system and policy are not perfect,engineering technology and agronomical technology are not supported,lack of water-saving concept.Drip irrigation is currently the most effective,most water-saving irrigation method in the arid region,with a water utilization rate of 95%.If the drip irrigation technology is promoted,the farmland production is guaranteed,and it is effective to alleviate the shortage of water resources.As a variety of intra-hydraulic flow path,the labyrinth-type waterway is a simple structure,a good hydraulic performance,and a low cost.In this context,based on the cross-sectional form of the maze flow path,the small-scale flow path of the rectangular cross section is used as the study object,and the small-scale straight flow channel,labyrinth flow path and bending flow path of the rectangular section are used to analyze the cross section.The ratio(W/h)has a variety of hydraulic properties of three different flow paths,which is designed to provide a certain theoretical basis for the development of high-performance intake.This article mainly obtained the following conclusions(1)In the small-scale straight flow channel with rectangular cross section,the head loss along the way and the average flow velocity of the cross section satisfy a linear relationship.When the water flow is in laminar flow,the head loss along the way is proportional to the first power of the average velocity of the section,and when it is in a turbulent state,the head loss along the way is proportional to the second power of the average velocity of the section.The changes in the cross-sectional area and cross-sectional ratio of the small-scale through passage have no obvious effect on the hydraulic characteristics of the fluid.(2)When the cross-sectional area of the labyrinth channel is the same and the crosssectional ratio is different,the larger the cross-sectional ratio,the smaller the sensitivity of the flow to pressure and the better the hydraulic performance.The effect of different cross-sectional ratios on the flow rate of the labyrinth channel is proportional to the flow channel area.The increase in the cross-sectional area of the flow channel is different,and the difference in the flow rate of each model of the labyrinth channel increases under the same pressure.For labyrinth channels with the same cross-sectional area,different cross-sectional ratios have a slight impact on the flow coefficient,and the impact will increase with the increase of the crosssectional area,and has no obvious impact on the flow index.(3)The interference length,head loss,local head loss,and local loss coefficient of the water flow in the continuous bend flow channel are directly proportional to the number of bends.Continuously bend the flow channel,the bending distance is within a certain range,the head loss,local head loss,and local head loss coefficient are inversely proportional to the bending distance.(4)The cross-sectional area of the flow channel is the same,and the number of bendings is the same.The interference length,head loss,local head loss and local head loss coefficient of the flow in the combined bending flow channel are proportional to the flow channel crosssectional ratio.(5)The larger the local loss coefficient,the more obvious the development of the vortex area,indicating that the local loss coefficient is directly proportional to the development of the vortex area. |
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