Detection Of Partial Blockage And Leakage In Long-distance Pipeline For Water Conveyance By Frequency Response Method

Transport though long distance pressured pipeline has the characteristic of steadiness, continuity, safety, reliability, being unpolluted, little material, small needed area and low cost etc. It is important to detect in time the location of leakage or partial blockage. In this thesis the leakage and partial blockage of single pipe system and series pipe system in long distance pressured pipeline for water conveyance have been studied in the frequency domain by using the frequency response method and water hammer theory, the relative pressure frequency diagram and relative discharge frequency diagram of the detected points have been analyzed, and the location together with size of the blockage and leakage have been determined. The main contents include:(l)Methods of detecting leakage and blockage in pipe have been systematically introduced.(2)The theories of water hammer and hydraulic vibration have been integrated for studying the blockage and leakage on the base of precursor's work. Typical transfer matrixes have been made, the transfer equation for calculating pressure head and discharge between two optional points in the course of fluctuation have been deducted in some boundary condition by using Laplace Transform.(3)The varies of relative pressure frequency diagram and relative discharge frequency diagram are different when the location and size of the blockage and leakage are different, which have been concluded from calculating the pressure and discharge of the detected points on single pipe as well as series pipe. The formula for calculating the location of blockage and leakage has been achieved; the size of blockage and leakage has also been determined by calculating the difference between maximum value and minimum value of the peak value in the diagrams.(4)The problems which should be further studied have been put forward.