Study On Flow Field Characteristics And Structure Optimization Of Spiral Labyrinth Pump

Offshore oil and gas resources have become an important form of energy in my country.As a mechanical oil recovery method,ESP oil recovery is widely used in the development of offshore oil and gas fields.However,when operating in a high viscosity and high gas environment,the ESP will There are cases where performance drops drastically or even becomes unusable.The spiral labyrinth pump has a simple structure and good pressurization,and is suitable for conveying viscous,or gas-containing media.Therefore,this paper conducts a study on the flow field characteristics and structure optimization of the spiral labyrinth pump to replace the electric motor operating under the condition of high viscosity and high gas content.submersible pump.In this paper,the external characteristics test of the spiral labyrinth pump is carried out by the combination of experimental research,numerical simulation and theoretical analysis,and the influence of the medium viscosity and gas content on the pump performance is obtained.,an MRF-CFX coupling simulation method suitable for the spiral labyrinth pump was proposed;the motion characteristics of the fluid in the pump were obtained through numerical simulation,the pumping mechanism of the spiral labyrinth pump was revealed,and the performance evaluation model was established based on the law of energy conservation.The model studies the influence law of tooth shape and structural parameters on performance;combined with the influence of different structural parameters on boost pressure and efficiency,the SW-CFX-DX co-simulation method is used to optimize the stator and rotor structures,in order to improve the delivery of viscous oil in the spiral labyrinth pump.It provides theoretical guidance on the performance of gaseous media.The specific work and results are as follows:Referring to the electric submersible pump of the same size and specification,a spiral labyrinth pump prototype with a flow rate of 100 m3/d and a speed of 2900 rpm was designed and manufactured.Influence rule of viscosity,air content and rotational speed on the performance of spiral labyrinth pump.The test results show that when the viscosity of the conveying medium is 200 cp,the efficiency of the spiral labyrinth pump is 45.5%,while the efficiency of the ESP under the same specifications and working conditions is only 16%.comparative advantage.Taking the spiral labyrinth pump prototype as a model for numerical simulation,the calculation accuracy and efficiency of the "Interior-SIMPLEC method" and the "moving grid method" were systematically analyzed.The MRF-CFX coupling simulation method,which is suitable for dealing with the fluid problem in the small gap at the dynamic and static interface of the spiral labyrinth pump,improves the computing efficiency by 40%,and reduces the error between the performance calculation value and the external characteristic test value to within 4%,indicating that the numerical simulation method can provide reliable data for the analysis of flow field characteristics and structural optimization.Through numerical simulation,the distribution law of fluid pressure,velocity and turbulence intensity in the spiral labyrinth pump in the axial,circumferential and radial directions is studied,and the motion characteristics of the fluid are analyzed,and the reasons for the formation of the pumping pressure of the spiral labyrinth pump are obtained.the pumping mechanism of the pump.Based on the law of energy conservation,the performance calculation model of the spiral labyrinth pump is established,the influence of different tooth shapes and structural parameters on the performance of the spiral labyrinth pump is systematically studied,and the optimal value range of each parameter is obtained,which is the structural parameter of the pump.The optimization provides data support.In order to improve the efficiency of spiral labyrinth pump performance calculation,a multi-condition full-parameter performance prediction method based on SW-CFX-DX co-simulation is proposed,which can obtain the predicted value of spiral labyrinth pump performance without recalculation.Compared with the actual calculated values,the average prediction errors of the efficiency and pressurization of this method when conveying viscous 200 cp medium are 2.60% and 4.08%,respectively;the prediction average errors of efficiency and pressurization when conveying medium with gas content of 30% are 3.55% and 4.89%.In order to improve the performance of the spiral labyrinth pump,the combination of SW-CFX-DX performance prediction and multi-objective genetic algorithm is used to optimize the structure of the spiral labyrinth pump with the goal of simultaneously optimizing the pressure increase and efficiency when conveying viscous and gas-containing media..The optimized structure under the condition of rotating speed2900 rpm and conveying medium viscosity 200 cp,the efficiency increased from 45.5%of the original structure to 48%,and the improvement rate was 5.49%.