chapter  3
42 Pages

Modeling for Pressure Wave into Water Pipeline

The development of hydraulic transition was paid more attention by N. E. Zhukovsky, A. Surin, L. Bergeron, L.F. Moshnin, N. A. Kartvelishvili, M. Andriashev, V. S. Dikarevsky, K.P. Wisniewski, B. F. Laman, V.I. Blokhin, L. S. Gerashchenko, V. N. Kovalenko, and others. The most detailed experimental and theoretical study of water hammer with a discontinuity in the flow conduits performed by D. N. Smirnov and L. B. Zubov. As a result of the research, they describe the basic laws of gap columns, fluid and obtained relatively simple calculation dependences. In the above works, there are methods of determining maximal pressures after the discontinuities of the flow. However, the results of calculations by these methods are often contradictory. In addition, not clarified the conditions under which the maximum pressure generated. There is little influence of loss of pressure, vacuum, nature and duration of flow control and other factors on the value of maximum pressure. The study of V. S. Dikarevsky for water hammer was included to break the continuity of flow. His work dealt with in detail, the impact magnitude of the vacuum on the course of the entire process of water hammer. Analytically and based on experimental data, scholars have argued that in a horizontal pipe rupture. The continuity of the flow occurs mainly in the regulatory body, and cavitation phenomena on the length of the pipeline are manifested. It investigates only in the form of small bubbles, whose influence on the process of hydraulic impact is negligible. As a result, research scientists have obtained analytic expressions for the hydraulic shock. They mention a gap of continuous flow, taking into account the energy loss, while controlling the flow and the wave nature. However, studies of V. S. Dikarevskogo were conducted mainly for the horizontal pressure pipelines and pumping units with a low inertia of moving masses. Researches of N. I. Kolotilo and others devoted to the study of water hammer to break the continuity of flow in the intermediate point. N. I. Kolotilo analytically derived the condition for the gap of continuous flow at a turning point of the pipeline when the pressure is reduced at this point (below atmospheric pressure). Studies have shown that the location of the discontinuity of continuous flow at a turning point depends, first of all, the profile of the pipeline. Protection of hydraulic systems against water hammer by releasing part of the transported fluid is the most widespread method of artificial reduction of the hydraulic shock. Devices that perform this function can be divided into valve, bursting disc and the overflow of the column. Development of algorithms for software simulation of transients by K. P. Vishnevsky was made for the complex pressure systems. It included the possible formation of discontinuities flows, hydraulic resistance, structural features of the pumping of water systems (pumps, piping, valves, etc.). However, a calculation of water ham

mer is adapted to high-pressure water systems for household and drinking purposes. K. P. Vishnevsky used “characteristics method” for the calculation of water hammer on a computer dedicated to the work of B. F. Lyamaeva [1-35].