管道末端水击压力计算及误区分析

Calculation and Error Analysis of Water Hammer Pressure at the End of Pipeline

引水系统的管道参数不同会导致管道末端水击压力波动形态差异较大,在工程仿真计算时得到的管道末端压力变化曲线难以校验。为得到管道末端压力波动曲线,首先结合经典的水击分类图,分析了引用传统水击计算方法时存在的误区。其次,从水击经典理论中的阀门端压力升高方程组出发,推导出各相水击压力升高值的通用形式,得到管道末端水压的简化计算公式,公式表明管道末端阀门开度是影响管道末端水压变化形态的重要因素。最后,利用数值仿真验证所提计算方法的可行性。结果表明,提出的管道末端水压简化计算方法与特征线法得到的压力变化曲线相似度较高,且表现出水压波动形态在管道末端阀门不同初始开度下的变化规律,方法简单实用。

Different pipeline parameters of the water diversion system will lead to a large difference in the shape of the water hammer pressure fluctuation at the end of the pipeline.It is difficult to verify the pressure curve of the end of the pipeline obtained during the engineering simulation calculation.In order to obtain the pressure fluctuation curve at the end of the pipeline,firstly,combined with the classic water hammer classification chart,the misunderstandings existing in applying the traditional water hammer calculation method are analyzed.Secondly,starting from the valve end pressure rise equation in the classic theory of water hammer,the general form of the water pressure rise value of each phase is derived,and a simplified calculation formula for the water pressure at the end of the pipeline is obtained.The formula shows that the valve opening at the end of the pipeline is an important factor affecting the shape of the water pressure change at the end of the pipeline.Finally,numerical simulation is used to verify the feasibility of the proposed calculation method.The results show that the simplified calculation method of the water pressure at the end of the pipeline is similar to the pressure change curve obtained by the characteristic line method,and it shows the change rule of the water pressure fluctuation pattern at different initial openings of the valve at the end of the pipeline.The method is simple and practical.