【摘要】 供热管网设计过程中,水力计算阶段管网已布置完成,局部阻力不必采用系数αj估算,只需根据管件的实际设置情况进行精细化计算即可。本文对两算例进行了局部阻力精细化计算,将各管段局部阻力与沿程阻力的比值即局沿阻力比α绘制成散点图,并与估算系数αj工程中的推荐值对比,二者偏差较大。热水管线算例中,α变化范围很大(0.03～3.31),其均值0.19与推荐值0.30相差较多,据此绘制的水压图差异明显。蒸汽管线算例中α在0.03～0.09范围内变化,其均值0.05与推荐值0.15相差三倍。因此对供热管网进行阻力精确化计算,既可以避免估算系数取值偏大造成的投资及运行过程中的浪费现象,又可以避免估算系数取值过小导致的热网容量不足。更多还原

【Abstract】 In the design process of heating network, the pipeline and fittings have been arranged in the hydraulic calculation stage. The local resistance needn’t be estimated by coefficient αj, but only needs to be calculated carefully according to the actual setting of pipe fittings.In this paper, the local resistance of two examples is calculated accurately,and the ratio of the local flow-resistance to the frictional flow-resistanceα, is plotted as a scatter plot and compared with the recommended value in the estimation coefficient αj,the deviation is large.In the example of hot-water pipeline, the range of α varies greatly(0.03 ～3.31), and the mean value αof 0.19 is much different from the recommended value αjof 0.30. Therefore, the pressure diagrambased on thecalculation results oftwo methods is obviously different.In the example of steam pipeline, the value of αvaried within the range of 0.03～0.09, and the mean value ofα0.05 was three times different from the recommended valueαj of 0.15.Therefore, the accurate calculation of the resistance of heating network can avoid the waste of investment and operation in the process of investment and operation, and also it can avoid the shortage of heat network capacity caused by the too small estimation coefficient.更多还原