CAJ | 학술논문

管道的当量粗糙度k是关键的水力计算参数，同时也是评估不同厂家同类管道制造加工质量的重要指标，因此对于一种新型管道，从水力学的观点，首要之事就是在水力试验室准确地率定k值。本文对3种管道进行了系统实验，结果发现用Colebrook公式确定的k值随着雷诺数Re的变化而显著变化。这是与实际相矛盾的，因为对于给定的管道在很短的时间内k应为常数。产生矛盾的主要原因就是测量参数存在不确定性。本文提出了定量计算管道阻力系数、k和流量的不确定度的方法，考虑了管径、管长、流量和水头损失以及量水堰宽度、高度与堰上水头等测量的不确定度。然后，以系统测量的实验数据为依据，研究了如何应用不确定度理论合理地确定k值及其不确定度大小。
관도적당량조조도k시관건적수력계산삼수，동시야시평고불동엄가동류관도제조가공질량적중요지표，인차대우일충신형관도，종수역학적관점，수요지사취시재수력시험실준학지솔정k치。본문대3충관도진행료계통실험，결과발현용Colebrook공식학정적k치수착뢰낙수Re적변화이현저변화。저시여실제상모순적，인위대우급정적관도재흔단적시간내k응위상수。산생모순적주요원인취시측량삼수존재불학정성。본문제출료정량계산관도조력계수、k화류량적불학정도적방법，고필료관경、관장、류량화수두손실이급량수언관도、고도여언상수두등측량적불학정도。연후，이계통측량적실험수거위의거，연구료여하응용불학정도이론합리지학정k치급기불학정도대소。
The average roughness height k of pipe is a key parameter in hydraulic calculation of pipe systems while it is also an important index for evaluating the manufacturing qualities of the same type of pipes made of different manufacturers. For a new type of pipes, the first thing from the view of point of hydraulics is to calibrate the value of k in hydraulic labs precisely to predict the capacity of water conveyance in the design of urban water-supply and drainage systems. The authors of this paper did the systematical experiment to calibrate the values of k for the three types of pipes. The results illustrate that the value of k found by the Culehrook equation varied significantly with the change of Reynolds number Re. This is a contradiction with the fact that the value of k should he a constant for the given pipe within a short time. One of the reasons is that there are the uncertainties in the measurement ,parameters. This paper presents the equations for calculating the uncertainties of the roughness coefficient, average roughness height and the flow rate of suppressed sharp-crested .weirs, on the basis of the ,uncertainties of the measurements of pipe diameter, length and head loss or piezometer head as well as width, height and head above crest level of weir for flow rate. Then, how to calibrate k reasonably is investigated by the systematical analysis of the uncertainties for the measured parameters.