Research Of Blockage Detection In Water Supply Pipeline Based On Pressure Wave Method Theory

In recent years,as the fast development of economic and urbanization,pipeline delivery system has been one of the five main transportation modes due to its steady performance,high efficiency,and low cost.But when it works for a period of time or other reasons,blockage phenomenon will inevitably happen in the pipelines.It will surely affect the normal performance of production and improve the operating costs.When blockage is getting more serious,it even causes the pipeline crack accident and threats people 's lives and properties.Thus,a high efficient and practical detecting method which can detect the blockages position and blockages amount would be essential and meaningful.The traditional pressure wave method combines wavelet transform and related analytical method to locate the blockage position without detecting the blockage amount.Considering the priority of pressure wave method in position the blockage amount,this method is employed to detect both the blockage position and blockage amount combining theoretically.The main research is as following:First,Two kinds of blockage models are introduced and two examples are simulated.One is with clogging in pipeline;the other has no clogging in pipeline.The pressure waves from two examples are compared to analyze effect of the blockage on pressure wave.It shows that there is a big difference between pressure waves from two examples,and when the blocking position is different,the pressure mutation occurs at different times;when the blocking amount is different,the size of the pressure mutation is different,which can be used to detect the clogging position and amount.Then,according to the propagation law of transient pressure wave in the pipeline,the method of blockage detection with pressure wave,which is mainly about quantitative research,is further studied.The result shows that the relationship between the local resistance coefficient and the pressure mutation amount,the blocking area of the pipe and the amount o f pressure mutation can be calculated theoretically.Also,a formula,which is used to determine the length of the blockage when the pipe is blocked,can be deduced.At last,pressure wave method is employed to detect the state of valve opening and clogging.It is validated by comparing with experimental data and then pressure waves in different points are analyzed.Results show that it is feasible to detect valve opening and clogging by pressure wave method.The detecting point,which is set on the incentive location is the most accurate in determine the blockage position,and the closer of the detecting point to the blockage the more accurate in determine the amount of blockages.When the length of the blockage is very short(the propagation time of the negative reflected wave in the blockage section is less than the closing time of the end valve),it is difficult to identify the amount of the pipe blockages in pressure wave method.