Hydrodynamic Numerical Simulation On Circulating Cooling Water System Of Thermal Power Plant

With the economy development, the requirements for power energy areincreasing in industry and daily life. Thermal power still plays a vital role in electricpower development, and it is necessary to ensure the cooling water circulatingsystem’s safe operation, as one of three systems of thermal power plants. Analyzingthe reason of water column separation and vaporization liable to occur in the system,choose reasonable protective measures and put forward appropriate operation scheme.With the complicated phenomena of the hydraulic transient process, such aswater column separation, vaporization, ect. liable to occur at the hump-points withinthe pipeline system of the cooling water system under the operation conditions ofnormal start-up/shut-down, or emergency shut-down of the water-circulating, thispaper is made with an actual engineering case in Indonesia, which adopts the methodof characteristics to simplify the complex dynamic boundary. According to thefollowing boundary conditions: the reservoir side, bifurcation node of pipeline, pump,outlet valve of pump, condenser, siphon well and drainage well, taking the wholecharacteristic curve of pump into account, establish a mathematic model of thecomplete system. In the calculation of hydraulic transition process in the power plantcooling water system, the key to the simulation is as follow: When the forebay’s waterlevel is design of low water level, how the moment of inertia effects on the controlparameter. When the forebay’s water level is design of low water level, how thecondenser’s diameter effects on vapor pressure. Under three operation conditions ofnormal start-up/shut-down, how the pressure changes along the delivery pipe and theimportant node, such as pump outlet, condenser outlet, bifurcation pipe. When theforebay’s water level is design of low water level, how pump outlet valve’sstart-up/shut-down effects on pumps, minimum water volume through condenser andthe pump’s maximum inversion speed.According to the calculation, we have put forward some feasible waterhammer protection methods to maintain the system’s stable operation in the paper. Based on characteristic method, calculating the valve opening and closing law is moresimply. Previous minimum condenser discharge is measured by the ultrasonic flow-meter and the condenser heat balance method, the equipment is relatively expensiveand the method of measurement is more complex, but the proposed method is moreflexible, more widely used.