| The single-stage centrifugal pump can't meet the requirements of daily life and manufacture so the large-scale double suction centrifugal pump applied as the society developing and technology improving. The double suction centrifugal pump has applied for irrigation, urban water, factories, and mine el. various water conservancy engineering because of advantages of high discharge and high head. The two impellers in double suction centrifugal pump is symmetrical arrangement which makes the axial force balance. Also the flow in this pump behaves complicated unsteady flow under the influence of asymmetric arrangement of spiral volute and the tongue. Especially, at the partial design conditions, the depravation of impeller and volute inlet flow field could lead to the pressure pulsation and impeller radial force.The pressure pulsation in pump especial the volute tongue is the important factors what effects pump stable operation, and the periodic axis change of radial force causes the vibration of the pump shaft so that the pump shaft and sealing ring damage.This paper investigated the radial force and pressure pulsation of DFES21-300 double suction centrifugal pump by numerical simulation, and the impeller and pump shaft vibration is researched by the method of fluid-structure interaction.Following is the main research work and achievements in this paper.1. The current situation of the vibration of double suction centrifugal pump has been showed and analyzed the current problems, and drew up the method and research institute combing the research objects.2. The double suction centrifugal pump 3D model is divided by UG software, and the grid is made by ICEM including grid independence verification. The monitoring points are located in the inlet, around the volute, and impeller flow path. Using the CFX CFD software to simulate the double suction pump at various conditions and analyze the internal flow field characteristics.3. Steady and unsteady calculations are at various conditions. The internal flow characteristics are based the steady results. The monitoring points pressure pulsation and impeller radial force results shows that the main frequency of pressure pulsation around the volute is the impeller frequency, and the shaft frequency including the monitoring points in impeller and suction outlet and other points pulsation characteristics are complicated. The impeller radial force is lowest at design condition, and the further away from the design condition, the higher radial fore.4. Analyzed the cavitation, cavitation distribution, and internal flow in impeller characteristics in double suction centrifugal pump. By comparing the radial force at various cavitation allowance conditions, the impeller radial force increased as the cavitation phenomenon intensified.5. The double suction pump internal flow field characteristics and solid phase distribution and impeller abrasion under the various medium solid-liquid two-phase flow parameters have been researched. By comparing the impeller radial force at various conditions, the results show that radial force decreased as the particle size increased when the volume concentration is constant, and the radial force increased as the volume concentration increased, so the changing of solid phase volume concentration effects the radial force.6. The ANSYS Workbench software and sequential coupling method are applied for modal analysis, static stress analysis, and the pre-stressed modal analysis of double suction centrifugal pump rotor, so the rotor dynamic characteristics at various conditions are acquired. The results show that the impeller maximum deformation is at the joint of impeller outlet and front cover plate. The rotating centrifugal force and the flow pressure on various discharges, various cavitation allowances and various medium parameters conditions show less influence on modal characteristics by comparing the pre-stressed modal characteristics. |
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