The Impact And Improving Of The Gas Rate Changes On The Oil And Gas Multiphase Pump Bearing Torsional Stress

The shaft is one of the important parts of the rotating member, for the multiphase pump, because of the complexity of the transmission medium, it is not only play the role of transferring power, but also play the role of withstanding bending, torsion and fatigue stresses, similar with the shaft in the ordinary meaning, the shaft is the very important, core components of the axial gas mixing pump. And because of the complexity of the multiphase pump structure, considering its tightness, volume size, material selection, economic, axial force, torque and other factors, making multiphase pump shaft design is a difficulty. Therefore, the strength and vibration determine the operating condition and life.This paper makes the detailed analysis and discussion on series of changes generated by shaft torque, gas-liquid mixing pump will produce pressure fluctuations in the import and export in the case of rapid change of the gas rate, and the shaft will generate stress concentration if the stress on it changes intensely, it will make certain impact on the life and stable operation of the pump shaft. In order to change this situation, when the gas rate increases, we guarantee the constant lift, which is the case of a small change in outlet pressure, we can ensure the normal operation of multiphase pump by increasing the speed.This paper makes a comprehensive analysis on the development status and trends of the multiphase pump, and system illustrates the design theory of the two-phase flow pump and the basic theory of CFD, introduces the models and numerical methods used in the process of CFD simulation. In the beginning of the article, use3D modeling software Pro/e to build a three-dimensional solid model of the flow field, and then guide the model to ICEM to mesh, make the flow field model, and then set the parameters, boundary conditions, turbulence model, the pressure coupling algorithm in FLUENT, achieve numerical simulation of flow field. For the processing of the entity structure, use Pro/e software for modeling, directly guide the three-dimensional model of the physical structure to Workbench to meshing and to make the structural analysis, get the relationship between the rate of gas and the stress and strain variations on the impeller blades and shaft, achieve the analysis of multiphase pump shaft torsional stress.Make the simulation analysis on the impeller blades and shaft of multiphase pump in different gas rates, get the curve between the gas rate and shaft torsional stress distribution and deformation distribution, make the improvement analysis on the stress concentration of the shaft, get the optimal allocation of the speed when the gas rate change but the head unchanged, and it has a good reference value on the improvement of the axial oil and gas multiphase pump design.