Analysis Complete Pump Characteristic Curves And Study On Its Impact On Hydraulic Transients Of Long-distance, Small-diameter, High-lift Pipeline

For realizing way to make the country powerful, our country has already built a number of major inter-regional water transfer project to address the serious imbalances in the distribution of water resources in order to achieve optimal allocation of water resources. But with our country West Development, vitalize the northeast China old industrial base, central section rises abruptly waiting for continue moving forward, many kinds of high-head, high-flow, long-distance water pipeline projects in difficult terrain increasing by gradually. A number of these projects are long-distance pressure pipe flow state and need pressure from water pumps to transmission. The water pump there exists starting up, shut-down in necessity, handles a fault, lose driving force or the valve action supplying water etc. Then the pressure piping in pipe flow will be from one steady state to another state, so that it will produce a series of dramatic pipeline changes in hydraulic pressure alternating transition phenomenon in the transition process..In transient process.it is sometimes able to arouse high or low water attack pressure, and it also may bring about the part pump accident fails to close a valve in time but to produce too big reversion speed. We have this kinds of hydraulic impact phenomenon been known as water hammer phenomenon. Water hammer problems is the greatest threat to pressure pipe distribution system. Most of the results of pumping water hammer incidents ranging from burst water pipes, check valve on the cap or shell were damaged a large number of leaks, causing a temporary supply disruptions and leading to re-pumping station flooded, and pump boat submerged by such serious incidents. So the water hammer process of the pump shut down transient study is the key to optimize the engineering design, to reduce construction costs and to ensure the project operation safe,and has important theoretical significance and practical value.This thesis summarizes the theory of rigid water hammer and the theory of elastic water hammer. The elastic water hammer is based on the assumption that liquid is compressible and tube wall is elastomer, so it accords with the objective realities that the derived equation is differential equations. The thesis introduces the derivative process of the water hammer differential equations, based on the theory of elastic water hammer.Accordingly,the thesis explain the basic principle of the method of characteristic curve and the derivation of finite-difference equations, and pump-side boundary condition equation. In addition, the thesis illustrates the importance of complete pump characteristic curves in the stop pump water hammer transient process and introduces several new calculation methods to simulate the complete pump characteristic curves According to the basic theory of water hammer, water hammer calculation methods and the equations of the pump-side boundary condition described in detail how to use the complete pump characteristic curves to calculate the water hammer,analysis and calculates the water hammer in a water diversion project in an area of Ningxia。Using Microsoft Visual C++6.0 to prepare water hammer calculation program, and then taking the results into Excel, using its superior data management capabilities to analyze the water hammer pressure diagram, giving better water hammer protection program.And numerical through several different specific speed pump and draw the boost(lower) pressure envelope diagram of water hammer. Determined that it is very important by comparing the total more accurate pump characteristic curve in the calculation of water hammer protection position.