| Inlet conduit is one of the most important parts of thermal power plant, recycling water pump station.Its main function is to lead flow smoothly to pump imports, which leads to create good pump hydraulic conditions.The well designed inlet passage not only can effectively reduce the hydraulic loss, liminate harmful vortices in the flow channel, to ensure the efficient operation of circulating pump, and can save water and electricity, reduce the engineering investment. Therefore, the analysis of circulating water pump station hydraulic characteristics of inlet passage for the safe operation of the pump, the rational use of energy, the overall efficiency of power plants, etc. all have great significance.Currently, the main research methods for hydraulic characteristics of inlet passage of the pumping station are physical model test and numerical simulation. The physical model test method is relatively mature, and observation results are reliable. Numerical simulation is short period, less expense, and can get the whole flow field data to facilitate the comparison of programs. Both methods have advantages and disadvantages. Therefore, in this paper the two methods are combined to analyze the hydraulic characteristics of inlet passage of recycling water pump station, getting the conclusion as follows:1) the water level along the flow direction being stabilizing Within the original design scheme in the flow. Water flow pattern is smooth near the inlet of Pump, no underwater whirlpool and swirling flow in Water-obsorbing room. However, the channel width is slightly less than the requirements of China's technology, Import of open channel and vertical proliferation existing surface and the bottom backflow. Water-obsorbing room surface with occasional collapse whirlpool. water-obsorbing room local point velocity larger than pump station design requirements.2) Shape design of modified scheme is basically reasonable. The water level fluctuation of inlet passage is small, water flow in suction pipe flows smoothly with no harmful swirl and homogeneous symmetric velocity distribution, and water level dropping surge height and minimum submergence degree are reaching pump design requirements when the pump opens and closes instantly.3) The numerical simulation results that the water surface profile, velocity distribution and water flow pattern are in good compliance with the measured data, verifying the correctness of the mathematical model and calculation method. The results real, credible and to verify the physical model is reasonable.4) Based on quantitative analysis of Axial velocity and X, Z direction velocity in bell mouth and suction pipe, axial velocity distribution is homogeneous symmetric.X and Z direction of the velocity distribution was basicly symmetric about the origin, in the opposite direction, positive or negative offset, and velocity value decreases to a large extent and Intensity of swirling flow in suction pipe won't form. Shows reasonable design of Vortex flow resistance and the obvious effect of the rectifier in bell mouth and suction pipe.5) By comparing the hydraulic characteristics of wedge and volute vortex resistance facilities, drew the conclusion that the local resistance coefficient in bell mouth of Wedge-shaped suction pipe is less than the one of Volute-shaped suction pipe; The flow line uniform distribution around bell mouth of Wedge-shaped suction pipe but the positive side flow line in bell mouth of volute suction more than flow line on back surface of the water. Volute suction more easily to form the bad Hydraulic Characteristics such as Swirling Tundish and Drift in suction pipe. The regularity of distribution of wedge suction pipeline's axial,X and Z velocity are stronger than In the worm suction chamber. Drew the conclusion that wedge facilities is better than volute facilities as to the effect of vortex resistance. |
PDF Full Text Request