Study On Seed Production Techniquues Of Tibetan Wild Elymus Nutans In Lhasa Valley

In recent years,with the increase of hydraulic power infrastructure construction,the construction of water conservancy and hydraulic power projects in Tibet has gradually become the focus of attention.Weir,as an important hydraulic structure in water conservancy and hydraulic power projects,mainly controls the water level and discharge of rivers or channels,and plays an extremely important role in the process of hydraulic power construction.Based on the multi-functional variable-slope experimental flume and standard right-angle triangular thin-walled Weir,the paper studies the triangular thin-walled Weir of the water intake hub of the Tibet Agricultural and Animal Husbandry Institute of Bayi District,Nyingchi Prefecture,Tibet Autonomous Region,with an average elevation of 3000 meters,and uses ANSYS-FLUENT software to simulate and verify the important parameters(water level,water surface line,discharge,discharge coefficient,Freud number,Euler number)that affect hydraulic power when water flows through the Weir,To provide theoretical basis and guidance for the future research on plateau hydraulic machinery in Tibet.The summary is as follows:1.In this study,the empirical formula of flow coefficient of triangular thin-walled Weir is obtained by theoretical analysis.Through the calculation and analysis of the flow coefficient in the original formula C the direct fitting method is used to obtain that the flow coefficient in the flow formula suitable for high altitude area is C=1.420,so the empirical formula for calculating the flow rate of triangle thin-walled Weir in high altitude area is as follows:Q=1.420 H^2.5.Combined with data processing and analysis,it is concluded that there is a good nonlinear relationship between the flow rate of triangle thin-walled Weir and the head of Weir,and the correlation coefficient is high.Therefore,the flow formula of triangular thin-walled Weir after the correction coefficient has practical application value for the study of triangular thin-walled Weir in Tibet.2.In this study,the main hydraulic system parameters of triangular thin-walled Weir are studied,These include Froude number Fr?Reynolds number Re?Weber number We and Euler number Eu,The test results show that,And the Fr of Froude number is less than 0.5,To ensure the stability of the flow,It shows that the data collected by the test are reliable and reasonable;The Reynolds number Re calculated between(2000×102-3300×102),And ray number(Re>1000),It shows that the flow is turbulent current.Therefore,The action of inertial force increases with the increase of Reynolds number,The effect of viscous force decreases with the increase of Reynolds number;The range of Weber number We(4.75×103-7.25×103)is obtained by experimental calculation,The size of the sink,When the flow increases,Both inertia and surface tension are increasing,But the velocity of flow inertia is greater than that of surface tension,A positive proportional relation.3.Through literature search and manual inquiry,this study shows that the flow coefficient is in the range of(0.5898-05855)and the flow coefficient is(0.594915-0.596645).The results show that the flow coefficient of high altitude is higher than that of plain,and the flow coefficient of high altitude is larger than that of plain.4.According to the relevant data of triangular thin-walled Weir test under different working conditions,the flow state of triangular Weir with different flow conditions(0.021 m³/s?0.031m³/s)is simulated numerically.Through comparison and analysis of computer numerical simulation and triangle Weir test,it is concluded that the numerical simulation can reproduce the flow state of the free interface of water and gas well,the measured free water surface elevation is in good agreement with the simulation results,and the hydraulic jump length calculated by numerical simulation fits well with the measured data,the error is 1.08when the Q=is 0.021 m³/s,and the error when the Q=is 0.031 m³/s.The numerical simulation can clearly reproduce the distribution state and vector size of flow velocity,and the pressure distribution in the triangular thin-walled Weir obtained by numerical simulation accords with the basic theory of hydraulic pressure.