【作者】 赵明；

【导师】 张杰； 袁一星；

【作者基本信息】 哈尔滨工业大学 ， 市政工程， 2008， 博士

【摘要】 安全供水是供水事业的首要课题,输配水系统的安全应包括两个方面,即水力安全和水质安全。本论文“输配水系统水力与水质安全”,旨在建立安全供水的整体观念,把输水——配水——用户用水的安全作为一个整体综合考虑。输水系统的水力安全研究是以“哈尔滨磨盘上长距离输水项目”为依托,研究内容是项目的组成部分。配水系统水质安全研究是以国家“863”课题为依托,研究内容是“863”课题的组成部分。论文深入研究了长距离输水管线集气、排气的原理,对形成的气泡进行了分析,求出了管线临界俯角。根据这个理念复核排气阀设置是否合适;对于磨盘山长距离输水管线221个排气阀进行复核计算,证明其布置合理,能保证排气通畅,不产生因气囊引起的水锤。长距离输水管线,地形复杂起伏较大,管线沿地形铺设,形成多个长度不等、高差不等的U形管,论文首次提出当竣工后首次通水,或维修灌水时,将产生U形管振荡,如果通水时流量过大,必将会引起振荡,导致爆管。因此,根据U形管振荡原理,提出水力平稳过渡的新理念,控制初次进水流量,使其逐步增加,从0.4m3/s逐步增加到设计流量5.5m3/s;保证了通水安全,使通水一次成功。通过实测和数值分析,得出PCCP管n值为0.0116,比沿用的钢筋混凝土管的n值(0.013~0.014)降低10.8%,对PCCP管的设计和运行具有指导意义。论文建立了长距离输水系统的瞬变流模型,用运动方程和连续方程对输水管线水锤进行模拟,用特征线法和反问题理论进行求解,获得满意结果,并将其应用于磨盘山输水管线水锤计算中,求出不同工况下的水锤包络线,模拟出输水运行过程中,最不利工况下不产生水锤的安全关闸时间应大于32分20秒。将该研究成果应用于实际输水运行中,避免了输水系统经常发生的水锤事故,保障了该系统的安全运行。利用实测和数值计算得出RKV DN600的活塞式调流调压阀阻力系数与开度之间的关系式,它为输水管线运行中的水力安全模拟奠定了基础。论文深入分析了配水管网“生长环”生成的机理,阐明“生长环”是电化学腐蚀、水中微生物、管网后沉淀共同作用的结果,它引起了管网水质恶化。通过实验论证了管径越小,水与管壁“生长环”接触率越大,消耗的余氯越多,铺设年代越长,管内的水质越差,停留时间(水龄)越长,水质污染越严重。而对我国的大、中、小城市管网状况统计可知,管网中水多在小管径低流速状况下流动,“生长环”对其影响程度增加。同时用分散分析法分析了在各种影响因素同时存在下,各因素及各因素的交互作用对配水系统内三卤甲烷形成的影响程度,得出加氯量的变化对三卤甲烷形成的影响最大,为55%。降低加氯量,对减少三卤甲烷的形成具有重要作用。对配水管网余氯在管道中传输与节点混合数学方程进行探讨,同时推求出不同连接方式的水龄模型。探讨了模型的求解方法,确定用基于时间驱动的拉格朗日算法求解余氯衰减模型。论文从水质、水量和水压全方位考虑,提出了管网规划、设计及改造的新方法—配水系统区块化;并将其应用到某市配水系统的水质模拟,结果表明,区块化后配水系统的综合平均水龄减小约20.1%,余氯消耗减小约12.6%。同时水压分布更加趋于均匀,平均水压减小约12.1%,与此相对应配水系统的漏水量也减小13.8%。这些结果充分验证了配水系统区块化的有效性。更多还原

【Abstract】 Safety is the most important subject to water supply, which includes two aspects, hydraulic safety and water quality safety. The major purpose of this study is to build an overall concept of water supply safety by considering water transmission- water distribution- water users as a system.The hydraulic safety of water transmission system was studied in this study as a part of the project named "Long-distance Water Transmission from Mopanshan Reservoir to Harbin City", while the water quality safety of water distribution system was studied as a part of the national "863" research project.Detailed studies on gas gathering and exhausting mechanism in long-distance transfer pipeline were conducted, and critical angle of the pipeline was also estimated by analyzing the mechanism of trapped air pocket formation. The results of calibration on 221 air valves installed along Mopanshan long-distance transfer pipeline showed that the locations of these air valves were appropriate and water hammer could not be occurred by air bag. Due to rough terrain, various U-tubes with different spans and levels were inevitable, which may result in oscillation even the destruction of the pipelines. Based on oscillation mechanism of hydraulic drop, a new concept of hydraulic stable transition was developed and it was recommended that flow test should be increased from 0.4 m3/d to 5.5 m3/d gradually. Finally, successful flow test was obtained by using the developed method. Moreover, roughness coefficient n value (0.0116) for PCCP pipe used was also calculated by actual measurement, which was lower than (reduced by 10.8%) current n value (0.013~0.014), and will provides an important basis in the design and operation for other similar projects.In this study, a transient flow model of long-distance water transfer system was developed, and motion equation and continuity equation were used for the simulation of water hammer in water transfer system. By using inverse theory and characteristic method, water hammer calculations of Mopanshan long- distance transfer pipeline were carried out under different working conditions. The simulation results showed that valve closing time should be longer than 32.3 minutes at the worst working condition. This value was applied to valve closing operation of Mopanshan long-distance water transmission and satisfied results were obtained. In addition, a relationship between opening extent and friction coefficient of valve (RKV DN600) was calculated and measured, which has laid the foundation for hydraulic safety simulation.The mechanism of "growth ring" in distribution system was comprehensive analyzed and studied. The results of the study indicated that "growth ring" is the results of joint activities of the chemical corrosion, physical deposition and biological reaction. The smaller diameter could result in bigger contact rate of water in pipeline with "growth ring". Aged pipeline and longer water age could result in contamination of water quality in distribution system. In this study, statistical analysis on the distribution pipelines of big, mid and small cities in Chine was carried out. The results indicated that in most cities the velocities in distribution pipelines were in lower levels, which may cause the contamination of water quality. Analysis of variance was used to analyze the influence of each factor and the interaction between the factors on the THMs formation. The result showed that the chlorine dosage variation had the greatest impact (55% in influence) on the formation of THMs. Therefore, reducing the chlorine dosage is of great significance to reduce the formation of THMs. Finally, the hybrid chlorine decay dynamics model was developed, and model solution methods were examined, then Lagrange algorithm method was developed for simulating the decay of residual chlorine.In accordance with current situations in water quality, water quantity and pressure of distribution systems in China, a new method-distribution blocking system (DBS) for network planning, design, and reconstruction was developed in this study. The new method was applied in the water quality simulation of water distribution system in a city, and results showed that the average water age and residual chlorine decay in the distribution system were reduced by 20.1% and 12.6%, respectively. Moreover, the pressure ranges in the distribution system trended to be more equal and average pressure in the distribution system could be reduced by 12.1%. Consequently, water leakage quantity could be reduced by 13.8% by using the developed DBS method.更多还原