Comparison Of Motor Arrangement Of Submersible Tubular Pump Device

Submersible pump device is a mechanical-electrical integration of pump and submersible motor.At present,there are two main types of submersible pump device:vertical submersible pump device and horizontal submersible pump device.The application and research of vertical submersible pump has a history of tens of years.The application and research of horizontal submersible pump(i.e.submersible tubular pump)only lasted for more than ten years.The submersible motor of the submersible pump device has two kinds of arrangement modes relative to the pump:the motor front arrangement(the submersible motor is arranged at the intake side of the pump)and the motor rear arrangement(the submersible motor is arranged at the outlet side of the pump).Vertical submersible pump device can only adopt the rear arrangement of motor because of its structural characteristics.Unlike vertical submersible pumps,horizontal submersible pumps have simple inlet and outlet conduits.The inlet and outlet flows are kept in horizontal direction,without turning in the inlet and outlet conduits.The flow pattern is smooth and uniform,which is obviously superior to vertical submersible pumps.The efficiency of pump devices is much higher than that of vertical submersible pumps.At present,the horizontal submersible pump device is evolved from the vertical submersible pump device,and the motor layout mode follows the post layout mode logically,forming the motor rear arrangement submersible tubular pump device.This paper puts forward that the motor arrangement of horizontal submersible pump device can be either motor rear arrangement or motor front arrangement,which can be called the motor rear arrangement submersible tubular pump device and the motor front arrangement submersible tubular pump device respectively.Further research found that the submersible tubular pump device with motor rear arrangement has some problems,such as bad flow pattern of outlet conduit,large diffusive angle of guide vane body and high requirement for sealing performance of electric secrets.The submersible tubular pump device with motor front can solve these problems well.In order to make the motor front-end submersible tubular pump device get more and better application,this paper uses the numerical simulation method to study the optimal hydraulic design of the inlet and outlet passages of the motor front-end and the motor rear-end submersible tubular pump device,and carries out the hydraulic performance,design of guide vane of pump model,motor seal,unit support structure and engineering investment of the two types of pump devices.A comprehensive comparative study of these aspects.The main research results are as follows:(1)The flow in the inlet conduit of the optimized motor front arrangement submersible tubular pump device contracted gently,uniformly and without bad flow pattern,which could provide a good flow pattern for the impeller chamber inlet of the pump;the flow in the optimized outlet conduit spread gently,uniformly and without vortices;the numerical results of three-dimensional flow field of motor front arrangement submersible tubular pump device show that the maximum efficiency of the pump device is 79.94%.(2)The flow in the inlet conduit of the optimized motor rear arrangement submersible tubular pump device contracted gently and evenly,with clear streamline layers and no bad flow pattern,which could provide an ideal flow pattern for the inlet of the impeller chamber of the pump;the main flow in the optimized outlet conduit deviated to the lower right area of the diffusion section,and there was a certain range of vortices in the upper left area of the diffusion section of the flow conduit;the numerical results of three-dimensional flow field of motor rear arrangement submersible tubular pump device show that the maximum efficiency of the pump device is 77.05%.(3)The head loss of inlet conduit is greater than that of motor rear,the head loss of outlet conduit is less than that of motor rear,the total loss of conduit is less than that of motor rear,and the efficiency of submersible tubular pump device with motor front is higher than that of motor rear.(4)The motor front arrangement tubular submersible pump device can directly adopt the original design guide vane of the pump model.When the motor rear arrangement,in order to make the guide vane body and motor segment connect smoothly,the diffusion Angle of the guide vane body of the original pump model must be increased,and the hydraulic design of the guide vane body needs to be modified according to the size and position of the submersible motor,so as to affect the hydraulic performance of the pump.(5)The submersible motor receives less water pressure when the motor is pre-positioned,and the submersible motor receives more water pressure when the motor is post-positioned.The motor front arrangement is conducive to improving the safety,reliability and service life of the motor seal.(6)The two supporting bearings of the pump shaft form a simple supporting structure for the impeller when the motor is positioned in front,and the supporting structure is reasonable.When the motor is positioned in rear,the support of the pump shaft to the impeller forms a cantilever structure,which affects the stability of the pump shaft system.(7)The length of the outlet conduit of the motor front arrangement submersible tubular pump device is relatively short,and the equipment such as no motor is arranged in the outlet conduit is easy to be designed as an upward inclined way,which is convenient for raising the bottom elevation of the outlet and reducing the investment in civil engineering;the motor rear arrangement submersible tubular pump device needs to minimize the motor shell size in order to reduce the diffusive angle of the guide vane body,which makes the requirements for the size and sealing of the motor and gear box higher.Increase unit investment.According to the comparison of hydraulic performance,pump guide vane design,motor sealing performance,support structure and project investment between motor front arrangement and motor rear arrangement submersible tubular pump device,it is suggested that motor front arrangement scheme should be preferred in submersible tubular pump device.The research results in this paper are of great significance and engineering application value for enriching the types of low-lift pumps and improving the hydraulic design level of submersible tubular pumps.