Design And Thermal Analysis Of Submersible Srew Pump Drive Motor

With the constant deepening of oil exploitation, the conventional beam pumping system has been difficult to adapt to the complex well conditions of the latter oil exploitation, and the submersible screw pump system driven by induction motor has high speed, so it is difficult to adapt to the oil with high viscosity and sand. Therefore, the research and development of low-speed, high torque, energy efficient submersible screw pump permanent magnet synchronous motor is important.Submersible screw pump permanent magnet synchronous motor is a vertical hanging motor. It uses segmented and slender structure for the stators and rotors. The stators are separated by magnetic isolation sections of copper, the rotors are supported by centralizer bearing, permanent magnets are fixed to the rotors, and the lubricating oil is filled between the stators and rotors.For the structural characteristics of submersible motor, two motor overall structural programs were presented, and the overall structural program was determined through comparative analysis. According to the overall structural program, the basic structures of the stators, the rotors, the upper and lower connector and thrust bearing were designed.View of the segmented and slender features of the submersible motor's stators and rotors, finite element software ANSYS was used to analyze the mode of the motor shaft, the natural frequencies and mode shapes during the steady-state operation of the motor shaft were calculated, and the speed region in which the motor shaft may occur resonance was determined.Unilateral magnetic pull has greater impact on the deflection of the submersible motor shaft, so the unilateral magnetic pull of a single rotor was calculated, and the deformation of the motor shaft under the unilateral magnetic was analyzed through static finite element analysis.Heating and cooling process of the submersible motor during operation are complex. The winding loss, core loss and mechanical loss were calculated and the heat transfer coefficients were defined by the knowledge of fluid mechanics during the steady-state operation of the motor when the well temperature was 70 oC , the two and three dimensional model of steady-state temperature field were established, the steady-state temperature field was calculated and compared with the theoretical value. Through the analysis that the impact of the surface heat transfer coefficients and the insulation materials on the motor temperature field, understanded the cooling situation of the motor.Finally, the submersible motor ground experimental platform was set up by the submersible motor, the submersible screw pump and the controller to test the loss and temperature, and the transient temperature field was analyzed by the loss and temperature datas which were obtained from the experiment and the finite element software ANSYS, so mastered the heating and cooling conditions through the compare with the results of the experiment from starting to steady-state operation of the motor.