摘要
为了更合理的计算管道输水的沿程损失,采用室内模拟试验的方法,确定流速与沿程损失之间的关系,并对常用经验公式的主要参数进行修正。试验结果表明:UPVC输水管道沿程水头损失随着管道流速的增大而增加,两者之间有较好的幂函数关系;常用经验公式中,谢才公式、达西-魏斯巴哈公式和《规范》公式的系数,即曼宁糙率系数、沿程阻力系数和摩阻系数均随着管道流速的增大先迅速降低,流速大于1.040 m/s后,变化较小,趋于稳定,各系数与流速之间呈幂函数关系;海曾-威廉公式系数变化趋势相反,系数与流速之间具有较好的对数函数关系。采用修正后的经验公式计算值与实测值接近,相关系数均达到0.997以上。因此,通过修正后的经验公式可提高计算精度,满足计算需求。
In order to calculate the accurate frictional head loss of the pressurized water transported by PVC pipeline, laboratory simulation tests were carried out to determine the relationship between the water flow velocity and the frictional head loss, and to correct friction factors of the experimental formulates frequently used. The results showed that, the frictional head loss increased with water flow velocity, and there was a good power function relationship between them;among the empirical formulates frequently used, Chezy formula, Darcy-Weisbach equation, and the empirical formulate recommended in "Technical specification for irrigation projects with low pressure pipe conveyance", their friction factors, Manning roughness factor, friction factors of head loss, and coefficient of friction resistance, decreased quickly first, and then decreased slowly when water flow velocity is larger than 1.040 m/s. Finally, they tended to be a constant value. There were good power function relationships between the friction factors and the water flow velocity. On the contrary, the factor of Hazen-William formulate increased with water flow velocity and had a good logarithmic function relationship between them. The values calculated by the revised formulations were approximately equal to the values measured, and their correlation coefficients were larger than 0.997. Therefore, the calculation accuracy could be promoted by the revised formulations, and the results would meet the requirements.
作者
张守军
ZHANG Shoujun(Pengyang County Water Authority,Pengyang,Ningxia 756500,China)
出处
《水利与建筑工程学报》
2019年第6期231-235,共5页
Journal of Water Resources and Architectural Engineering
基金
国家科技支撑计划子课题“规模化灌溉管网优化设计及安全调控技术”(2015BAD24B02-01)
关键词
UPVC输水管道
流速
沿程水头损失
沿程阻力系数
经验公式
pipe irrigation
water flow velocity
frictional head loss
friction factor of head loss
empirical formula
