The diameter of the impeller balance hole in a centrifugal pump is closely related to axial force.Thus,to select the appropriate diameter of a balance hole is crucial for balancing the axial force of the centrifugal p...The diameter of the impeller balance hole in a centrifugal pump is closely related to axial force.Thus,to select the appropriate diameter of a balance hole is crucial for balancing the axial force of the centrifugal pump.After the validation of the CFD method and the grids independence study,the characteristics of flow in the hub cavity have been analyzed in 4 cases with different diameters of balance holes.The leakage rate of the liquid in the hub cavity of the centrifugal pump is calculated and compared with the test result.According to the research,when no balance hole exists,the distribution of liquid velocity in the core area of the hub cavity exhibits axial symmetry,and the circumferential velocity component is approximately 0.4 times of the impeller's rotational speed.When the balance hole exists,the distribution of liquid velocity in the hub cavity does not exhibit axial symmetry,and the circumferential velocity component is larger than 0.4 times of the impeller's rotational speed.The radial leakage velocity on the turbulent boundary layer of the pump cover will increase with the increasing diameter of the balance hole.展开更多
Aiming at the problem of runner unbalance in the compounding cavity of the upper and lower cover of the correction tape box, the plastic injection analysis software Moldflow was used to optimize runner balance. First,...Aiming at the problem of runner unbalance in the compounding cavity of the upper and lower cover of the correction tape box, the plastic injection analysis software Moldflow was used to optimize runner balance. First, the 3D modeling software Proe was used to establish the geometric model of the upper and lower cover of the correction tape box, and introduced into the plastic injection analysis software Moldflow. Secondly, the upper and the lower cover of the correction tape box were meshed and the initial gating system was designed in Moldflow. Filling analysis of the initial scheme of the correction tape box combined cavity showed that the runner of the melt was not balanced in the mold cavity. Finally, the runner balance optimization analysis of the cavities was carried out. Through optimization, the time unbalance rate of the melt in the mold cavity decreased from 28.6% to 0.7%, the pressure unbalance rate decreased from 42.0% to 4.2%, and the pressure distribution in the cavity was more uniform in the whole injection process.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51269010,51236006)This work was supported by the Fundamental Research Funds for the Central Universities(Grant No.Z1090219041)+1 种基金the Science and Technology Plan Project Funds for Shaanxi Provincial Department of Water Resources(Grant No.2019slkj-15)the Basic Natural Science Research Program of Shaanxi Province(Grant No.201WLM-58).
文摘The diameter of the impeller balance hole in a centrifugal pump is closely related to axial force.Thus,to select the appropriate diameter of a balance hole is crucial for balancing the axial force of the centrifugal pump.After the validation of the CFD method and the grids independence study,the characteristics of flow in the hub cavity have been analyzed in 4 cases with different diameters of balance holes.The leakage rate of the liquid in the hub cavity of the centrifugal pump is calculated and compared with the test result.According to the research,when no balance hole exists,the distribution of liquid velocity in the core area of the hub cavity exhibits axial symmetry,and the circumferential velocity component is approximately 0.4 times of the impeller's rotational speed.When the balance hole exists,the distribution of liquid velocity in the hub cavity does not exhibit axial symmetry,and the circumferential velocity component is larger than 0.4 times of the impeller's rotational speed.The radial leakage velocity on the turbulent boundary layer of the pump cover will increase with the increasing diameter of the balance hole.
文摘Aiming at the problem of runner unbalance in the compounding cavity of the upper and lower cover of the correction tape box, the plastic injection analysis software Moldflow was used to optimize runner balance. First, the 3D modeling software Proe was used to establish the geometric model of the upper and lower cover of the correction tape box, and introduced into the plastic injection analysis software Moldflow. Secondly, the upper and the lower cover of the correction tape box were meshed and the initial gating system was designed in Moldflow. Filling analysis of the initial scheme of the correction tape box combined cavity showed that the runner of the melt was not balanced in the mold cavity. Finally, the runner balance optimization analysis of the cavities was carried out. Through optimization, the time unbalance rate of the melt in the mold cavity decreased from 28.6% to 0.7%, the pressure unbalance rate decreased from 42.0% to 4.2%, and the pressure distribution in the cavity was more uniform in the whole injection process.
