【作者】 王为民；

【导师】 吕宏兴；

【作者基本信息】 西北农林科技大学 ， 水利工程， 2007， 硕士

【摘要】 长距离输水工程的水力过渡过程的计算,已经成为工程安全运行重要课题之一。禹门口供水工程就是一项长距离的压力管路输水系统,由于其管线长,管线敷设地形较复杂,输水管路的安全防护问题成为供水调度的关键问题之一,管路系统事故停泵水锤压力是影响工程长期安全可靠运行的重要因素,本论文主要针对其输水系统的事故停泵水锤问题进行计算分析。水锤计算方法很多,有分析法、图解法、特征线数值解法;图解法易于掌握,并能反映水锤现象的全过程,但由于其工作量大,且有很多因素如管路摩阻忽略不计。这对短管路来说影响不大,但对长管路摩阻是不能忽略的,有时在图解时把摩阻集中于起始端,这和实际情况也出入较大,加之在作水锤线时可能出现累积误差,对某些复杂管道的计算很麻烦。特征线解法可避免上述缺点,该法不仅物理概念明确,而且求解精度高,对复杂的非稳定问题用计算机求解,结果迅速、准确。论文分析研究了一、二两级泵站在各种组合工况稳态运行情况下水泵的工作点以及泵站系统的运行状况,并对水泵变速调节进行了水力模拟计算,为确定水泵运行时最优工况提供了理论依据。根据供水工程长距离压力管路输水系统和多点布置进排气阀的特点,通过对水锤计算方法的比较,采用有压管道非恒定流数值模拟计算的特征线法,对利用二阶段缓闭蝶阀作为压力管路的主要安全防护手段时,若干种不同工况组合的供水系统的事故停泵水锤问题进行了模拟计算,起始管路最大压力超过规范要求,严重威胁压力管路的运行安全。因此,必须采用蝶阀与进排气阀共同作用联动防护。文中结合当量管道法和调整波速法确定了水锤计算中的相关参数,建立了山西省禹门口工业供水泵站工程进排气阀计算模型,并对各种工况进行了模拟计算,结果满足规范要求,同时为工程的优化设计及安全运行提供了一定的理论依据和技术支持。更多还原

【Abstract】 Hydraulic transient calculation of long-distance water supplying project has become one of the most important subject in the project safe operation. Yumenkou water supply project is a long-distance water supply project. Because its long-distance pipes and complex laying topography, the protecting question of the pipeline has become a key question for the water supply attemperment. The pressure of pipeline system in the state of pump ceases abruptly and abnormally, which is an important factor that affects the safety and credibility of pipeline. This paper mostly calculated and analysed water hammer problem when the pump abnormally ceases abruptly.There are many methods to calculate water hammer such as analytic method、graphic method and the mathematics method of diagnostic line. The analytic method is easy to use and it can reflect the entire process of water hammer, but it has too much workload. Besides it neglects too many factors such as resistance coefficient of pipeline, which do not harm big effect on short pipelines. However it can not be neglected for long pipelines. Sometimes resistance coefficient is centralized at the begining of pipeline when using graphic method, which have big differences in actual situations. Besides it may have cumulative error when using graphic method, and it is difficult to calculate some complex pipeline. The mathematics method of diagnostic line could avoid those shortcomings. It do not only have definite physical conception, but also have great solutional precision. It is quite prompt and precise using computer to solve complicated unsteady problems.Through the pump working point and the operation status of pumping station system of first and second stage pump stations on various conditions of stable operation were analysed and studied, and the pump gearshift adjustment was calculated by hydraulic simulation, we gave the theory basis to make sure the best operation mode when the pump was operating. On the basis of the characteristics of the filling and emptying system of long-distance water supplying project and intake-exhaust valve with multiple point measurement, by comparing the water hammer calculating methods, we adopted the eigenfunction method of numerical simulation calculations of the transient flow in conduit under pressure, made simulated calculations of water hammer caused by power failure on various conditions of water supply system, when taking two-moment delay-shut butterfly valve as the safe measure of pressure pipeline. We got the most pressure of the beginning pipeline exceeded the criterion and threatened operation safety of the pressure pipeline seriously. Therefore, we must take butterfly valve and intake-exhaust valve as joint defense. Combining the method of equal-mete pipeline and adjusting wave-velocity method, automatic subsection method in water hammer calculation is established and has applied in water hammer calculation of intake-exhaust valve in this paper. Not only establishing the calculation-methodological rationality and easy-using, but also putting forward the practical application-conclusion of intake-exhaust valve in water supply project, through the application and calculation-analysis in Yumenkou water supply project establishment of the calculation model of enter-exhaust valve.更多还原