Study On Water Hammer Protection In Long Distance Water Pipeline With High-lift And Multi-fluctuation

For long-distance water transmission pipeline with high-lift and multi-fluctuation, on the one hand, long-distance, high-lift requires, the negative pressure pipe sections along water pipelines can not be too long on the normal water supply conditions, or on a non-stable conditions may cause water hammer damage accidents—external pressure buckling on pipeline; On the other hand, there are several hump along the pipe sections, water hammer of cavities collapsing with water column separation easily occurs, leading to serious harm caused by water hammer. In this paper, analyze characteristic of long-distance water transmission pipeline with high-lift and multi-fluctuation, and describe water hammer protection from the following aspects:According to the basic moving rules and some common characteristics of gas and water, using the "three lines, three points," features unit method, combined with flat gas-liquid two-phase flow pipeline research theory of Professor Ma Ding, analysis flow characteristics of long-distance water transmission pipeline with high-lift and multi-fluctuation pipeline. And as the characteristics of long-distance water transmission pipeline with high-lift and multi-fluctuation, analysis water hammer protection characteristics of pumping station and pipelines , and offer choice principle of protective measures.Describe the basic equations of water hammer briefly, and boundary conditions of pump on different conditions are given, as well as exhaust valve, surge tank and pressure relief valve water hammer and other commonly used protective measures. Based on the basic principles of water hammer calculation, combined of various types of boundary conditions, set up a mathematical model for calculation of water hammer, then compile calculation program of water hammer protection with C + + language.Finally, take water transmission pipeline from water plant to one million cubic waterpot and industrial park water transmission pipeline as example, simulate,caculete and analysis with compiled calculation program of water hammer protection. Based on the result of calculation, give the optimal integrated water hammer protection measures as follows:1. Install two-stage hydraulic control valves outlet of water pump; 2. In accordance with the exhaust requirements under normal operation, install Exhaust valves of the steady speed and cushioning along the pipe;3. At water catchments main pipe outlet of pump and special positions (high pressure or low pressure), install over-pressure relief valve or box-type two-way surge tower.It is a valuable reference to protect water hammer for similar engineering.