中文摘要：

有压管道的水力特性是管道设计工作的依据和前提。为研究山地灌溉输水管道水力特性,该文建立山地灌溉输水管道水动力学数学模型,运用计算流体动力学数值模拟方法,对有压灌溉管道中凸起管段的水力特性进行模拟。该文以输入流量为控制变量,计算管道水流能量损失,分析了Re与管道凸起段135°弯头局部阻力系数的关系;研究输水管道凸起段水压和流速分布特性。结果表明：当Re〈5.0×104时弯头局部阻力系数随着Re增大而迅速减小,当Re〉7.0×104时弯头局部阻力系数趋于稳定,

英文摘要：

The hydraulic characteristics of pressurized pipelines are important for irrigation system designs. The hydrodynamics irrigation pipes in a hilly terrain were analyzed here using a computational fluid dynamics model. The energy losses in the pipeline were calculated with the input discharge as the control variable.The relationship between the Reynolds number and flow resistance coefficient of a convex section（a 135° elbow） was analyzed.The pressure and velocity distributions are presented for the pipeline.The results show that：1）when the Reynolds number is less than 5.0×104,the flow coefficient of the elbow decreases rapidly with increasing Reynolds number;2）when the Reynolds number is more than 7.0 × 104,the flow coefficient is nearly constant;3）when the Reynolds number is in the range of 2.3×104and 7.0×104,the flow coefficient ranges in 4.12 ~ 0.37.The pressure on the backside of the elbow is high,while the inside pressure is low.The velocity distribution is just the opposite with a low velocity near the backside of the elbow and higher velocities near the inside.