Numeration Simulation Of The Flow Field For The Inlet Of The Double-suction Centrifugal Pump

As the double-suction centrifugal pumps for a wide range of applications, whether in factories, mines, urban water supply and drainage or a farmland irrigation and drainage can be used.Compared with single-suction pump, a larger flow, good suction on the property.And compared with mixed-flow pump, higher head.The analysis shows,to a large extent,it influences the cavitation of the pump that the inlet incidence angle of the blade of the semi-spiral chamber of the double-suction centrifugal pump. The positive inlet incidence angle of the blade is beneficial to reduce the hydraulic loss of flow,and has little effect on the efficiency. On the contrary,the pump cavitation resistance will be significantly worse by using the negative inlet incidence angle of the blade.This topic analyzes the calculation of the inlet incidence angle of the blade.At the some time,because of the traditional design methodology of the inlet of the blade of the semi-spiral chamber of the double-suction centrifugal pump,empirical coefficient range over a large distance,and the results are not accurate.Under different flow, empirical coefficient is calculated,reducing its scope,designed for such pumps provide a reference.In the present paper, the three-dimensional turbulent flow is simulated through the whole flow passage of the model 1200S56 large-scale double-suction centrifugal pump through CFD software,its main contents are as follows:1.The semi-spiral chamber of the double-suction centrifugal pump of the three-dimensional model was established and meshing,the good grid model will lead into Fluent in its whole flow passage numerical simulation.2.In carrying water,the impeller of the double-suction centrifugal pump from the inlet to the outlet,the pressure first decreases and then rises.At the same radius,the pressure of the front side of blade is higher than the back of blade, the same to speed.The distribution slightly uneven distribution of the phenomenon of speed or pressure of impeller is caused by the special structure of the semi-spiral suction chamber of the double-suction centrifugal pump.3.Through numerical simulation,analysis and calculation of the interior flow field,the exact scope of empirical coefficient m is given for the type pump for reference.4. By CFD numerical simulation,design flow and over design flow is analyzed. The inlet incidence angle of the blade is calculated at the flow line of the impeller front shroud,the impeller back shroud and the middle.The inlet incidence angle of the blade of 1.0Q and 1.2Q both is positive,but under 1.4Q,the inlet incidence angle of the blade of the flow line of the impeller front shroud and the impeller back shroud is negative.The cavitation of the pump were analyzed and explained.5.Through calculation of vuR of the flow line of the impeller front shroud,the impeller back shroud and the middle under 1.0Q,the result shows it meets empirical formula vuR=const.