山地灌溉管道含气囊运动的水力特性研究

摘要

By using the 75mm PVC water supply pipe,it established the mountainous region irrigation pipe model,and researched the hydraulic characteristics of mountainous irrigation pipe with air movement. In the experiment,it changed the pipe flow and observed the airbag movement of the pipe protruding parts. Through measuring the flow rate and pipe hydrodynamic pressure,it discussed the relationship between the 135 ° elbow local resistance coefficient and Reynolds number. The results show that:a)As the flow rate decreasing,the pipeline airbag volume amplifies and the air bag to pipe flow resistance increases. b)as the Reynolds number increasing,the 135 ° elbow local resistance coefficient decreases. When the Reynolds number is less than 2 × 104 ,the local resistance coefficient decreases rapidly with the increase of the Reynolds number,and finally tends to be stable.%采用直径75 mm的PVC给水管，建立了山地灌溉管道模型，对有压灌溉管道中凸起管段气囊运动的水力特性进行研究。试验中改变管道中流量，观察管道凸起部位气囊运动情况；通过量测流量、管道动水压强，分析了雷诺数与管道凸起处135°弯头局部阻力系数的关系。结果表明：①随着管道输水流量减小，管道突起部位气囊体积扩大，气囊对管道水流阻力增大；②随着雷诺数增大，管道凸起管段135°弯头局部阻力系数减小，雷诺数小于2．0×104时，局部阻力系数随雷诺数增大而迅速减小，最后趋于稳定。